NATO soldiers are inside NATO countries. Poland and Romania are NATO members.

NATO soldiers are still in NATO countries as opposed to russian agents that seem to have fun doing targeted assassinations and microwaving people's brains outside of Russia

Russia invaded Ukraine in 2014, and they still haven't left. You're right that the same can't be said for NATO, but in a totally different sense.

Russian soldiers are still in Moldova (see Transnistria), Georgia (see Abkhazia, Ossetia), Ukraine (Crimea, Donbas), Belarus.

The US and to a lesser extent Russia as well.