Why are manhua translators not as 'good' when translating chinese works to english?

Why are manhua translators not as 'good' when translating chinese works to english?

Don't get me wrong, I'm grateful for their hardwork but it's just that 90% of the manhuas I've read have bad translations or they're so unnatural to the point that I think that a human didn't translate it. One thing I noticed that made me think they're all MTL is because they mostly use passive voice (ex. AV= She ate the lasagna, PV= The lasagna was eaten by her.)

I'm obviously not chinese but I'm an English speaker so I can at least pinpoint what's natural or not. Also the lack of slangs, in Korean and Japanese mangas the translators often use slangs (even if the raws didn't particularly use slangs) just to show characterization.