While you may be more correct when speaking about absolute balance (since you're ranked 1, so arguably positioned best to know), I think most people not close to your skill do not see / play / distinguish the differences / balance in exact terms or evaluation as you do. Or shorter, weaker players find different things stronger, or harder to overcome.
I understand / assume the post is meant for base Behemoth, since that is the one most tradeable, and not Behemoth in general (all tiers). I'll refer to Behemoth as B. Quoted parts are from your original post. Numbering points for referencing them later.
Here are my opinions / reactions:

1. "forces you to run cheap kingmovers to defend against it" - I don't see how it forces that. It does force champions (special mentions to Bomber, Snake, partially Frostmephit), but not their moveset. Kingmovers make defense easier, but not particularly / specially vs B compared to other things. I'd argue that minions blocking their way, since they "take 10 moves to get anywhere" would be a downside to kingmove defenders vs B.

2. "Anything that isn't cheap, and anything that isn't a kingmover, is by default a disadvantage against a Behemoth user." No, because (1), and because some more expensive champions might be / hard for B to deal with, e.g. SK++, Pyro, or can just ignore B threat of minion kills and make bigger threats (on King, more expensive champions) themselves. I do agree, that B is giving you advantage of relatively cheap champion trader, but so do other pieces (HA, MF, ranged / magic from afar). B just has different flavor to how it helps trading champs for cheap. You could say similar 'impossible to overcome efficiently' analogy for different units with their own flavor / advantage.

3. "synergizes with itself". Same as (2) for units with different flavors. The more blockers (armor) you have, the sooner opponent runs out of counters, the more long range / magic ... , double traders (MF, Gemini) ... . The more you invest / build for one idea / tactic, the more you can take advantage of it generally, but get screwed harder when countered. Specialise for easy wins and easy losses, generalise for difficult wins and difficult losses. I like easy ones, because it's time efficient farm + gimmicks / total control which are very fun for me when they work. I imagine you don't like any losses, because that's the only way to be on top.

4. Lifestone - it is its purpose to revive what helps you win more. Do more B help you win more ? We're back at (2) + (3).

5. B is RPS, ranged is RPS, magic is RPS, immunities of any sort are RPS, blocking is RPS, I guess we should be used to RPS by now. Maybe they're RPS to different extents, everything can not be same, but I find there are more and worse examples of RPS than B. You're guaranteed / forced to have 7 champions (what B forces as its RPS), unlike other exmaples of RPS. Is the answer RPS enough ? Depends, RPS.

6. "synergizes unbelievably with Minotaur" I don't agree. Well enough to be played, yes. Many other things are synergistic, that's what we want, and build army around. I agree with main-gi's example of Phoenix + nexus here. Is some other combination of B + x + y + ... even more RPS ? Aren't we all trying to build more RPS setup to be harder to play against ?

7. "only good thing". Well, absolutely no, or absolutely RPS, because what is good or not for this case is 100% personal preference. It's not your business / problem, if I use threat squares or not, so (insert stfu comment that doesn't sound as aggressive :). 'The only good thing we could do in life, is remove electricity from any use by mankind, because it would force people to actually do what they have electricity do for them now, and most of it even impossible to do. Like, playing, commenting on, discussing CEO' - rephrased your view of threat squares, trying to highlight how it sounds / what it means from my pov.

8. "boring kingmover". Again, some find kingmovers easier to play with, so you say aye, I say nay. RPS.

In conclusion, I don't agree with anything being horrific con. The only thing that seems horrific is the "pro" that forces thing onto me / others, but that preference of yours isn't my concern :) , as it shouldn't be vice-versa.