Some/many people can't separate the accusation from it being shown to be true. During that period of time (years??), it's a distraction for those people from the other problems like handling vaccine distribution, relations with China independent of COVID19, etc...

Yes, if this were a narrow academic research project looking into the origin that was left de-politicized until there was an outcome that would be great. Unfortunately this whole thing was born political and China hasn't done itself any favors by always being so hush hush.