reporting

Yes, several times and usually quickly. Why have you sent so many- you may have unintentionally exceeded some threshold to limit griefing

The more important question is, has a certain GamePress user notorious for his tantrums been banned for recently making death threats?

I made once a report on a spoofer..
I used to play in the middle of the night in a small village with 5 gyms, 2 in the open field.
After swiping the gym my mon got kicked out within 5 minutes while nobody was around. (it kept happening)
Reported that person after a couple days and never saw him again.

They are more likely to act and respond when there is an issue with premium items or if you claim to feel threatened.

I had a troll account that targeted me and the name mentioned that I eat dicks. I said I felt unsafe and want the account banned. Niantic responded immediately. Mentioned that I should contact the police (yeah right and say someone wrote I should eat dicks online.) and decided that the account would have a forced name change but not a ban.

I've send entire reports plus pictures if Blissey towers from someone with all and the same name accounts. Also reports of other spoofers.

Never a response and nothing ever changed. Time waste to the fullest

I view them more as placebo effect. Reporting a spoofer at least makes me feel i did something but it's very difficult to see if it had any effect