In reality these are massive organisations of people who want to do good and protect people from actual dangers and repeats of actual harmful incidents. So I think framing the motives as malevolent isn’t helpful because the motives aren’t malevolent.
I think it’s much more reasonable to ask why these things arise. Eg maybe the government says “how will you stop something like x happening again” and they say “well it would have been really hard to detect but we were slightly suspicious of them. If only we could get a warrant to find out what they were talking about...”. And this probably seems reasonable to the minister who still thinks these intelligence agencies are steaming open letters or tapping into phone lines.
It doesn’t even need to be the case that people know these laws would work/be useful, all they need is to feel that they would. And this can quite easily happen without any malicious intentions.
Other things one could imagine happening are finding warrants annoying because they feel like a formality and feeling that the pause in the process potentially causes harm. Or seeing the whole “I ask my ally to spy on my citizens” process as a silly way to get round an annoying loophole. I can imagine something like this happening in a multinational company and if you see intelligence allies as actually working together in a team it doesn’t seem so crazy to see it as a silly legal formality to allow the actual teamwork. So (to say the same thing again) I don’t think these things arise from bad intentions.
A final thing is that many people in these intelligence organisations seem to care about how this surveillance is done in an ethical way (although some people don’t). Eg note here that they want to get this ability with a warrant (perhaps they really want it warrantless and plan to get it or perhaps they feel like they were burned by the various revelations and don’t think they could get it anyway).
Compare this to the way much of the modern mass surveillance we are exposed to every day is planned where there is virtually no ethical oversight at all.
