Total BS. If you were trying to be constructive, you would mention ways in which FBT is better. Instead, you feel the need to tell him -- and look like an idiot in the process -- that it is 100 times better than anything he writes. How is asking a person if he/she feels offended, hurt, upset, etc. that a person who does not get paid does a better job than he/she does NOT controversial? If you are going to be an asshole, just be one.
If you are actually interested in making his writing better or something that you deem better, give him ideas, instead of making statements that show your limited mental capacity. Have a little class.
P.S. Another note, if you were trying to improve his writing, email or PM him with your comments. You know exactly who is he is and where to get a hold of him. Zero reason to put this in a public setting if you were not trying to be controversial.