When I stumble upon these obtrusive ways to hide content I'll just leave. If possible I'll try and find that content somewhere else.

What works best for me are instead the polite and discreet banners asking me to allow ads on their domain. Also because probably I know their ads won't be flashy and annoying.

I guess every website makes a choice based on their tone of voice and what works best for their audience, but I'll always feel morally obligated to let them know the obtrusive manners won't work on me ;)

Yeah yeah, cool. The fact that hovering a block makes the text disappear is just bad UX, though.

And especially http://flexboxin5.com/

What approach do you guys prefer? How are you nesting components using BEM or other conventions?

Another annoying problem related to the line height is how the selection is displayed while hovering a text:

Ladies and gentlemen... and here's how to infringe dozens of copyrights in one single page!

Did we?

Anyway I think that what you point out conceptually explains the reason why they used a two line icon, but if we discuss about whether the hamburger icon is a UX-antipattern I don't understand how this = icon could be a good choice.

The next generation hamburger icon will be an even less user friendly single line.

It's official: we definitely need the Downvote button.