I'm reading over it, and I fail to see the problem.
You are talking about skilled trades like construction (or deconstruction), machinists, and industrial manufacturing.
Generally the businesses involving the traditional skilled trades require that individuals have experience. This is a good thing.
Usually with small businesses you will see things like "We have 30 years of industry experience", meaning the five people who founded it may have 14 years, 7 years, 4 years, 3 years, and 6 months experience, respectively.
Those key people, the ones with 14 years experience and 7 years experience, are critical to the success or failure of the business. Those are the ones who really know how to do the job. They have the experience to keep things safe. They have the experience to know when things are not quite right, to know what kind of things need to change, and the ability to supervise projects and train the new guys.
In order to get a professional license in those skilled trades you need experience. It is a good thing. Once you are experienced and individually licensed you can start out on your own venture, but until you get the license you are not considered skilled enough to manage and run the projects on your own.
Most of the businesses ideas mentioned require not just professional licensing, but also bonding. That requires further evidence that you can do the job safely without jeopardizing the public.
It is not that they don't want your business. It is that they want skilled tradespeople to do the job, or at least to supervise the work, for everyone's safety.
This is a common them in government, trying to save the citizens/subjects from their own stupidity for their own good. However, regulations are always a bad idea. Free market consumer interaction will always be more efficient and lead to more wealth because it allows greed, the motivation of just about everything great in this world, to do its thing. What do you think would happen if all the regulations were abolished tomorrow. Would we have an epidemic of poorly run and dangerous businesses a few years from now? Of course not, because consumers don't run charities. They want the best value for their money, always. Usually they will want people with experience and a good reputation because their is a smaller risk involved. They also might want to go for the cheapest guy despite him not having a track record (risky). Regardless, they should be able to choose. Government regulations aren't necessary to pick and choose suitable businesses and unsuitable businesses. The consumers can do it much better and without paying paper pushing bureaucrats. Crappy businesses fail and good businesses prosper.
The sad thing is that "protecting the people" isn't even the whole story as people have said above. Reducing competition is a huge factor not only in Detroit but also on a nationwide scale as anyone familiar with the dealings of large corporations and the government will tell you. Disgusting if you ask me
Maybe this example seems too extreme for you; maybe when you said "regulations are always a bad idea," you didn't really mean always, just sometimes. In that case, here's a slightly more down-to-earth example:
Imagine, again, that you are a producer of food. You could increase your profits if you could make your food cheaper to produce. You discover that by using extremely dangerous pesticides or other chemicals, you get to sell a higher percentage of your crop than your competitors. Your food might be less safe, but you don't know this for sure, and the pesticides might be damaging the water supply, but this does not bother you: government inspectors never come to examine your means of production, and you simply do not reveal what you're doing. In fact, you can just lie, and say that you're not using chemicals at all.
Your competitors could hope that people somehow catch onto what you're doing, but they don't, at least not quickly enough. Your competitors realize that, by the time any detrimental health effects of your food become public knowledge, they will no longer be in business, since your prices are so much lower. To save their business, your competitors realize that they have to start using chemicals, too. Eventually, citizens might discover that the chemicals in their food has devastating long-term effects, but by this time you have made enough money that you have left the food-production business altogether. You live in your mansion while everyone who eats the food you sold them dies of cancer.
The simple fact is that, even the most hardcore, free-market theorists know that regulations are necessary; no one who studies the economy disputes this. There's disagreement as to how much or which regulation is necessary, but any attempt to model an economy that has scarce resources and actors motivated by greed reveals that a completely unregulated market is bad for almost everyone.
I should clarify. When I said "regulations are always a bad idea" I meant government mandated regulations are always a bad idea. As you can see I'm hinting at the fact that quality control is important for consumers, but there is no reason it needs to or should come from the government. Anything provided by the government can be done better by the private market. Food certification boards provided by the free market could impose certain regulations on food producers in order to put a little stamp on their product that consumers trust. Furthermore, because of competition between certification boards and food producers the quality and safety of food would surely increase. Don't you think YOU should be able to choose which products are suitable or not? Or are you the kind of person that believes in the infinite wisdom of elected saviors that will guide us to the promised land? There is nothing special about government apart from the fact that it cannot fail no matter the results it produces.