I too thought perhaps it is because some are flying in the same areas (could be 1 or 2, or a dozen, but favourite places for them nonetheless), and if those particular areas are not some of the reported places with unusual stutters or freezes, then they don’t see what all the bluster is about.
While I mostly fly all over the place - I know, attention span of a toddler - until this last Sim Update I never had any of the performance issues. I tended not to fly over big cities nor in airliners so perhaps I was missing those issues due to that.
I made a thread here in the forum for people to report where they are experiencing these problems - so that other people who are trouble-free can see if they stay that way.
There are quite a few ‘problem locations’ here if you’d like to test some of them to see:
Recent Update Stutters - Where In The World Is It Happening To You? - Community / General Discussion - Microsoft Flight Simulator Forums