Two comments
1. How does he know facebook manipulated the “like” ratio on his impeachment page?
2. Personally I generally don’t do politics on facebook. I use it to connect up with distant old friends and that’s about it.
It's impossible that there's any other explanation--if you read his column, you will see that's all it could be. I've seen Facebook bury things. I know they do it--they've admitted they do it. They buried his page's reach--they do it all the time to conservative pages.