I agree completely with everything you said. Particularly, it certainly is relative, which is why I have a big problem with categorical statements suggesting if you deposit you're a loser and can't play poker. In my response to the OP I said that depositing $50 every month might be a problem if his goal was to become a winning player, because if he's applying himself to learn the game and still requiring that many deposits, then he's probably doing something wrong. But if he considers $50/month an entertainment expense because he just enjoys the game, then there's nothing wrong with that at all. More power to him. I spend way more than that a month on frivolous entertainment.
I still argue that it's an indisputable fact is that the act of depositing by itself has no bearing on skill. If Phil Ivey sits down to a new poker site, he's going to deposit or P2P a starting bankroll -- he's not going to start at freerolls, LOL. I'm not Phil Ivey, although I would venture to say I play a better game than most only because 90% of poker players are losing players and I'm not. But even when I started out and was a losing player, I preferred to deposit $1000 and play 25NL than to endure freerolls and penny stakes to get there. I was more motivated to get better because I had real stakes on the line, and playing against better players will grow your game a helluva lot faster than playing only equal or lesser players (especially bad players). And before someone points it out: Note I didn't say playing better players is better for your winrate, but rather it's an investment in your education that can pay dividends later. Now of course I'd rather sit at a table of lesser players, because I can better adjust and understand how they play, but can also hold my own against regs.
These days I only deposit when I join a new site. It might be only a small amount, a few buy-ins, to try things out. If it looks like I'll settle there, I deposit big so that I can play the stakes I'm accustomed to. Occasionally I'll withdraw a large chunk of my roll to fund a vacation or other large purchase, leaving myself a small nut to play with, then decide it's not enough to keep me interested so I redeposit to play bigger.
And LOL at the very idea of playing "high stakes play money" instead. As if that means anything. No thanks, I'm playing to win real money and to test my skill against (and learn from) real players. Outside of something like a CC League Game, where there is more on the line than money, I have no time for play money.
Point being: there are many valid reasons to deposit, so to insult people for doing it is just being narrow-minded and ignorant about it. And in case it's not obvious, it tilts me.