It's a legitimate question. Any answer other than environmental activists have increased/decreased by x is not an answer to the question. If it's an emotionally loaded response (e.g. Seriously? People are murdered while you quibble!), it's a non-sequitur.
Language/communication doesn't work the way you argue here. There is context. OP's question would be valid and common for science on e.g. the connection of total brain cancers and smartphone usage.
No. The cynicism is the insistence that it doesn't matter.
> ...which derails the conversation
If the answer were "There has been a decrease in the total number of activists, therefore the record is worse that the absolute numbers imply" would you make this accusation? No. No you would not.
You would insist, correctly, that it was very relevant. You would rightly look with suspicion upon people who insist that the question "derails the conversation"
The "derails the conversation" accusation is itself a cynical attempt to control the conversation
Likewise you wouldn't discuss a rise in Al Qaeda terrorist attacks in relation to US population growth, or cartel excutions in relation to Mexico's birth rate. What you are interested in is the number of organized, state-like, violent offenders only, not the pool of their victims.
I hope my point gets across. Not a native speaker.
And I especially don't appreciate some of the histrionics of the "Don't question the accuracy!!" side.
Headline: "There is a 50% increase in the child-crushing rate!" Me: "There's nothing in the article that tells us how many children are being crushed, exactly. Is this a big problem? Small problem?" You: "You monster! Children are being crushed! Stop quibbling about how many! Even One. Single. Child. is too many!!"