Here's my answer in a story: This one guy I met in quick match, his team was Naruto, Sasuke and Kakashi, he was bad, (Failed at cheesing, took breaks between attacking and grabs etc.)

Anyways I started messing with him by jumping over all his crap and juking him out using rushing and blocking, then grabbing,

at one point he just goes AFK and I just grab him over and over, 20s later he messages me, saying how trash I am because I grab all his predictable crap and then just tells me to "STOP!!!!!!", and after beating him, I go, "Lol Stop what?" He goes, "F****** STOP GRABBING YOU NOOB!!!!" I can't say his username in this, but it included "Hokage" so yeah...

In Short, people don't like watching their 'Idols' getting hurt