The subject is csam
Discussion
I think csam is a direct object, with the subject being filters.
What?! 😃 Human speech, Sir, not coding now.
Filters on coffee against csam = good
Filters in chicken soup against csam = bad
...is the equivalent. The focus is on the on the double standarts.
I'm not talking about code. I'm referring to parts of English (human or otherwise) usage.
https://www.perfect-english-grammar.com/subjects-and-objects.html
Alright, I'm no native speaker, so instead of subject I clarify my statement and modify the term to: topic.
The topic is csam.
To be most precise: the pro-filters argument for both networks is the fight against the spread of csam.
They’re putting csam in coffee now?!? Bastards!
The subject is spam more broadly, ie any unwanted/unsolicited communication to your device. Your messaging app and email provider already have features to prevent strangers from flooding your inbox with garbage. Giving users the ability to abuse the system makes the experience worse for everyone except the spammer.