The argument used by anti-seat-recliners is that when someone reclines, it takes up the space of the person behind.The right to enjoy the space implied by buying a seat doesn't enter the equation, and therein is the rub.
The flaw with this argument is that they have the option to maintain the total amount of space if they too recline.
Why must the argument be 'I don't recline so no one else should either' rather than 'if everyone reclines there is no issue'
There are obviously some exceptions to this... it seems the passenger in that particular last row had no recline at all. That's the fault of the airline... or the passenger buying a 'basic' fare with no seat selection, rather than the recliner.
There are options for anti-recliners to avoid seats where someone can recline into them.