...I think it's a bit over the top to ban for a font size but honestly, if I was a mod I would be tempted to do the same.
Honestly, I don't see what's wrong with just using the default text size/font/color for regular posts though. There's a reason it's the default and why size 1 cyan isn't...Because the default is easy and pleasant to read for everybody.
Don't even get me started with people who use stupid colors for everything they post. Cyan and light pink? Really? If I have to highlight somebodies post to read it, I probably won't read it.
Default is too mainstream. Get on my level. I am an individual.