I do have a friend who is a diamond malphite main since season 3. I don't think he would play him for so long if he didn't find it fun.
Just like the filthy soraka mains, maybe they find something fun in depriving it for others.
Edit: To be fair, I was once a Malphite main too. I didn't go tanky tho. I was full ap balls to the wall fuck everybody build.
I am a Tahm main and I technically find fun in denying people kills. Definitely feels more interactive/risky,fun than Janna's disengage playstyle. The retreat nerf was well deserved, Tahm is too tanky to get retreat bonuses too.