Why would this be rude? Yes it is not that nice but I would not find this rude, I've purchased the seat and if it reclines and I want to recline for whatever reason isn't it the person's right to do so? Yes pitch might tight, but seeing this as rude is unjustified in my opinion. Just to be clear - I normally do not recline on these SH, but if someone before me reclines, I don't think I have the right to judge.
When you purchase a seat, and if the seats recline, so be it - you should board with certain expectation and not certain privileges especially imposing it on other people. If you don't want someone to have their seat recline into your face, than purchase/select a bulkhead or whatever row that will not have a seat in your face.

The same goes for the OH cabin, if you have a rollerboard and a backpack, i feel that your expectation is one rollerboard above and your personal item below the seat - rude would be if pax stuffs all their belongings up there and therefore taking other pax space above.

I know above comments might bring this topic OT.... but this is my view - yes I too would not like it, but to label someone rude is a bit too far. Maybe you should start flying Ryanair (I believe all seats don't recline there?)

Cheers!