It doesn’t make it ok for the one taking advantage. However it does make a difference to the one on the receiving end. This is true about many inyanim of good middos. For example, it is a aveira d’oraisa to take revenge or bear a grudge. So if someone wrongs you, and you forgive them according to Halacha, that doesn’t mean that what they did was ok. It’s just that we believe Hashem can give everyone what is coming to them — it is not our job to do the accounting.
So I’ll agree with popa — is this person really a pushover, and doing all these things because they can’t stand up for themselves, or is this someone who is strong enough to rise about the pettiness of others and do the right thing anyway? Chazal actually praise in very strong terms “those who are insulted, and don’t insult back, who hear their shame and don’t respond”
Lehavdil one of my favorite quotes from Frances Hodgson Burnett is
“There’s nothing so strong as rage — except for what makes you hold it in.” There is a difference between being a pushover and being someone with strength of character. But in either case it has nothing to do with making the doers actions any more correct.