For starters, they are by far the worlds largest video game company. They own shares for a good chunk of gaming companies worldwide, for some even a majority. They own WeeChat and are involved with Discord. If nothing else, they are just way too big and hold way too much influence - that’s never a good thing.

They are known for censorship and are involved with the chinese goverment. You won’t find many games the chinese goverment disagrees with and since they have a majority share in most large esport titles, being overly critical of china could end your career.

Some of their own games are known to be blatant rip offs, companies they invested in tend to get worse with mtx.

TL;DR: They are too big, hold too much data and have a bad track record.