Regulation raises the barrier of entry for startups. Fewer startups means less competition. Less competition means less incentive for the incumbents to do "the right thing" in any field, be that hiring, ecological impact, consumer rights and so on.
When it comes to the economy, we should legislate and tax externalities. For everything else regulation is uniformly bad.
OK, fine. Let's remove all forms of regulation, shall we?
Someone joins your company and starts leaking all your intellectual property. It is all good, though, because legislation related to that doesn't exist.
A developer joins your company, and shortly after uploads your entire code base to github. That's OK due to lack of legislation saying otherwise.
A sysadmin changes all the passwords and asks you for a ransom to unlock your production database. That's also OK.
Your ISP randomly makes your internet 99% slower and then asks you for an exorbitant amount of money. That's also OK.
The accountant forged your signature and stole all the money. That's also OK.
Your customers randomly decide to not pay you. That's also OK.
Your employees start dismantling the office and taking furniture and equipment home. That's OK.
The mailman shows up wearing the company swag you ordered. Doesn't matter anymore.
HR people upload a spreadsheet with everyone's personal information and salaries to the Internet. That's OK.
Some larger company sends some gangsters to force you to sell the company for a fraction of its price. That's OK.
As you can see, saying "regulation is bad" is nonsensical. Without certain guarantees, businesses cannot exist.
I believe you are confused. Nobody is disputing the rule of law (and especially contract law) and the role of government in upholding it. What you are describing is pretty much anarchy and nobody is arguing for that.
I think the distinction between rule of law and regulation is fuzzy. Different people will draw the line in different places, with a heavy bias towards the current system for any given jurisdiction. (Devil you know.)
As a thought experiment: How would you solve those problems with your hands tied behind your back (i.e. you don't have a government to rely on)? Just try one - assume you're in a fictional universe and writing a novel or something.
Anywho, the problem with this trail of discussion is that you can come up with an infinite amount of "problems" and libertarians can likewise come up with a "solution" to each one. However your rebuttal would always be yet-another problem because the original "solution" didn't cater for some arbitrary corner case or something basic that you assume can only come from a society with a government.
E.g. "Your customers randomly decide to not pay you. That's also OK."
Answer: Have an escrow organization that both parties trust. Rebuttal: "Your escrow organization decides it doesn't like a certain legitimate business and won't accept your trade." Or "Your escrow organization's owner is buddy-buddy with your customer and he decides to not keep their part of the bargain". Okay - "contracts", followed with "but who will enforce the contracts", etc etc.
As a side note: A lot of the time libertarians and anarcho-capitalists don't "pick" lack of regulation out of practicality, but rather out of plain moral principle. A lot of what is considered "regulation" and "rule of law", when stripped of it's noble/protective aura, is just authoritarianism and bully-like behavior.
Without a monopoly of violence, you have 3 alternatives:
a) Multiple entities keeping each other in check, in perpetual competition...
b) One faction becomes more powerful than the rest and eventually assimilates the rest or turn them into vassals.
c) Factions decide to ally up and either assimilate the rest and make vassals out of them.
Basically, smaller fish gets eaten by larger fish. The world is just like a large prison where you have to either become a large entity or belong to a large alliance otherwise you're fucked.
We have had and currently have A, B and C, we just don't "see it" because it has an aura of "Democracy" and "will of the people". If we truly had freedom, it would be part of society, every government, the UN and considered a fundamental Human Right for individual groups of people to voluntarily group together and decide to "leave" their state/nation/entity/vassal/government/faction, and form their own "monopoly of violence" within their geographic area.
But we don't have that. We belong and are forced under subjugation to our individual governments without any say in the matter other than "voting" and "community participation". We can dress it up any which way we want, but we're forced into a relationship by virtue of birth and we have no option to leave.
When it comes to the economy, we should legislate and tax externalities. For everything else regulation is uniformly bad.