Timmy Turner never wished to get rid of poverty, discrimination or slavery so he sucks objectively
There was en episode where timmy wished to see what the world would be like if he didnt exist and it turned out chester got cosmo and wanda and wished away poverty. its possible he wished away discrimination and racism too since in that timeline he was considered the objectively best and most selfless person to have fairies.
so while timmy does suck, he sucks even more for undoing all the good that chester did by wishing to exist again.