It's essentially pointing out the biggest issue with the article and then shrugging it off, while obviously putting a lot of effort into the writing.
Or you could post GIFs yourself. Maybe that seems like too much work?
Asking whether I'm willing to provide my own gif isn't quite a fair measure. The author has the code running and he himself commented on the need for moving pictures. I have partial code and no personal investment in this.
I have however written a few articles about stuff I've done for my own work and wherever it seemed relevant I've taken the time to produce and include video. That's been a lot less effort than writing the text, even when it's required a number of changes in the scenes and code.
(By sub-pixel they mean more finely determining the endpoints of the lines on an arbitrary grid finer than the output pixels — NOT physical display sub-pixels.)