I'll try to type more slowly.
But some people can't post the complete ante or blind on their turn if they don't have chips, so how does that make a difference now? Maybe I'm just dumb and don't get it. If I have less than 1BB and I'm in the BB, I'm posting less that I'm supposed to on my turn, am I not? So how is this any different?
If a player lacks the chips to post the big blind on his turn, he is still eligible to win the pot containing any multiples of his contributed amount matched by all other players. He is posting less, but is also entitled to win less (than if he posted the full big blind amount). Same thing in a regular ante tournament where ~any~ player doesn't have enough chips to post his full ante amount: he is still eligible to win a multple of his contribution (times the number of antes posted) -- he is posting less, and therefore eligible to win less.
If, in a big blind ante tournament, the antes are posted by one player (the big blind position) for the entire tournament. If rules state that the table ante must be posted first (fair for all, since nobody gets to skip posting antes), then a player without sufficient chips will only be eligible to win back his own chips and nothing else (unfair to the big blind player).
And if the rules state that the big blind is posted first (fair to the bb player), then he gets to skip his scheduled turn of posting the table ante (unfair to the other players at the table who did post table antes).
Either way, an inequity exists that is simply not present if individual antes are posted (or if antes are not used at all).
And it does address the problem with the button ante if BB is posted first as the player does have a opportunity to profit.
Nope. If using a button ante, the ~button~ player must post the table ante for the entire table (and the big blind player posts just his big blind amount). If posting that table ante takes the button's entire stack, then he is only eligible to win his own ante amount, and cannot win any other chips (since he didn't contribute to the pot except for the antes). Again, an inequity that can be avoided by not using table antes.