Because 'researchers' and 'russian spy agency' sounds very different. Former are motivated by desire to shed light on questionable behavior, the latter to inflict damage on their adversary (while engaging in worse practices themselves).
Competition is good for the public. If American and Russian spy agencies call each other out on bad behaviour, everyone profits.
Only if the behavior they call out actually happened. If they start fabricating evidence of bad behavior that never happened then that's not a good thing.
Even if it was the KGB instead of Kaspersky that discovered this it doesn't change the fact we put spyware into hardware firmware.
Their motives are irrelevant if their findings are verified.
I've got no problem with anyone inflicting damage on the NSA. The enemy of my enemy is my friend, and all that.
What do you mean by worse practices? Are you saying Russian spy agencies have more sophisticated capabilities? Do they target more innocent people?