Why is it rude for people who took the trouble to get an A pass and to get to the airport early to have their choice of seats, even if those seats happen to be window and aisle? Obviously you don't like the middle seat; maybe the couple doesn't either. They made the effort to get the best seat choice; if you had been there earlier, you could have had it.
I say this from experience...my husband likes the window, but if I don't take my Xanax, I need to use the restroom more than once (nervous bladder from flying). If I don't feel like crawling over the middle person, I take the aisle. It's not my responsibility to worry about the seat preferences of others and to modify my life accordingly. If you don't like middle seats, get an A and get there early. Don't put the blame on couples who got there before you.
Barb