Resident Anarchist Linguist to the rescue!
The Libertarian definition seems to be "totally unregulated market" which in my experience instantly degenerates into oligopoly or monopoly market, typical of crony capitalism. If "ultra-capitalist" is not that, what would it be?
Tell me please: where did you have this experience of living in a totally unregulated market? I'd love to try it out myself!
I believe that a relatively free market can only be sustained if it is regulated by a government that is commited to it and is stronger than any individual supplier (or consumer), or any small group thereof.
However, a strong government and proper regulation is necessary to keep a market free
Oh dear, slavery is freedom, war is peace.
The sad thing is that by now probably the only thing which might make you realize the contradictions in your Belief System (BS) is 5grams of dried mushrooms

on a more constructive note:
Total freedom in the sense of absolutely no restraint, is certainly never desirable... My need for individual liberty does not demand that I have the freedom to coerce and murder, and economic entities should certainly be held to the same standard. THAT is the problem that needs to be solved: how do we prevent the players in the game from bending the rules in their own favor, thus cheating the other participants? The answer is surely not as simple as government regulation - that is just another cheating mechanism.
I don't claim to know what the ideal answer is. I imagine that there probably is no ideal answer, really. But I do know that empowering regulators is just arming the enemy.
I think you're on the right track. What needs to be changed imo is the thing that causes government regulation to exist in the first place, which is our culture. Our collective operating system. Because it hasn't been consciously updated for the era ultra-high acceleration of knowledge and technological progress, it is full of self-destructive bugs and plain old stupidity. This is why people (like you) feel, that "total freedom is certainly never desirable" - because they fear what all the people with their messed up operating systems might do, once "given total freedom".
That is of course a straw man. You are never given freedom. You can only claim freedom and by doing so change your own mental operating system. Some people will still choose to have harmful operating systems - we should be trying to help them...or who knows, maybe their kind serves a specific function in society. In any case it is a good idea not to provide them with tools to amplify the consequences of their destructive behavioral habits (i.e. government).