Your response Diddlydo fails under even the merest of scrutiny.
At 22.43 you stated "I'd love to know how many posters on this site are graduates - not too many I fear."
When asked what difference that made, you responded at 22.51 with "Brainpower".
When THECORBYLOON asked you if you would be able to identify graduates from the way arguments are framed, you responded at 23.13 with "I'd start with those who don't know the difference between "its" and "it's""
If not knowing the difference between "its" and "it's" is your measure of the start of a lack of "Brainpower", then it has to follow that not knowing the difference between "thats" and "that's" is also a measure of a lack of "Brainpower".
Gulliver, it would seem, does not know the difference between "thats" and "that's", and therefore using your measure of a lack of "Brainpower", Gulliver must be lacking.
Graduate or not, it is implied in your comment that a measure of what constitutes "Brainpower", is knowing the difference between "its" and "it's" or "thats" and "that's", and therefore it is further implied that those who do not know the difference are, for want of a better word, thick.