I think some are missing the point.

The issue is not whether they should recline or not, of course they are entitled to do so.

My issue is instead of:

1. Checking what is going on behind you (i.e. if you fly enough to be in F you certainly should be aware of what might be going on behind you).

2. Or at worst, slowly reclining so that the person behind you has time to make adjustments.

In the recent case this happend in hour 2 of a 3 hour flight. After 2 hours you have a bit of a comfort level that the person in front of you is a non-recliner.

I can come up with about a dozen things people are entitled to, which can be handled badly (i.e. you are in the window and need to use the restroom, do you just push your way by the person in aisle seat or do you let them know you need to get out?).