Someone is being inconsiderate by expecting the person in front not to make themselves more comfortable by using a facility built into their seat.
Someone in front who reclines a seat despite knowing it will affect someone behind is also inconsiderate, e.g. during meal times.
Bottom line, if you are 6'5" and decide to travel in Y, you know what you are going to receive and its your decision alone and thus your responsibility.
I agree with Tightslot that conflict in an aircraft is best avoided and you must take responsibility for your decision.
Here's hoping that your journey goes as well as it can.
BTW, I travel over 100 flights per year and as I wish to work on board, I pay the difference between Y and C to buy the space necessary to do this.
So please no lectures about the cost of premium class as it is many thousands of euros a year out of my wallet and I pay this gladly as I realize that Y is not designed to do serious work in and don't complain about people reclining their seats meaning that I can't open my laptop with a 30" seat pitch.