I'll kindly say this: while it might be technically bikeshedding, accessibility on the web is important and it only gets better when we call it out, respectfully, every chance we get. OP should have chosen better words, but the sentiment is valid.

It's very likely that as a high ranking HN article the owners of mender.io will read these comments and improve their blog. I don't have sight accessibility issues and I struggled to read this content.