Because he's a degenerate scam artist who influences young men to do things which are harmful for society. Society needs standards.
Please if he helps young men go to the gym and improve mental health then what's the problem
That's not what Andrew Tate did. Andrew Tate tells men that they are worthless unless they're wealthy, strong, and promiscuous like him, and then extracts money from them so they can attend his "hustle university" and learn surface-level Investipedia knowledge from a moderator on the Andrew Tate discord server.
People like this should absolutely be ostracized. Being mistreated by society does not give any of us an excuse to be fucking stupid.
"Then who's vice-president, Jerry Lewis?"