Allegedly it's based off a few fringe comments that Media Matters found, with mostly single digit points:

https://www.reddit.com/r/The_Donald/comments/c5sbpm/reddit_q...

Those aren't representative of the sub. What's the real reason?

I don't think anyone has a scientific answer on what is "representative" of the sub besides it's clear support for the president, but honestly it doesn't seem out of line with my experiences of the_donald.

Thank goodness we don't run the country based on possibly biased anecdotes

Fortunately, reddit has not yet achieved statehood.