I have good results when I either submit these via the “Report Abuse” form or when I appeal rejected in game reports like this one:
I have noticed that the answer is worded carefully
But the portals are definitely being removed when I do this.
I don’t think their stance has changed, but it feels like different teams look at the in game reports, and I expect those to be rejected and have to be appealed. I only do the in game ones when I don’t have time to write up a report.