For a long time, from the late 90's until roughly 2012, IE was the most popular browser. You had no choice but to work with it. If it didn't "work on IE", it didn't work.

I don't think flexbox really started being used until 2013 at the earliest, the comment I replied to was complaining about 2022 and a flexbox bug in IE. This 2012 thing doesn't seem to relate at all to the subject.

on edit: I know it was in WD in 2009 but I'm pretty sure it was around 2013 that people started playing with it. I think it started being popular in 2014-2015.

My comment was more about the prevalence of IE in general, not flexbox specific. There were tons of IE quirks that had to be dealt with.

Yea and people over exaggerated about it just like people over exaggerate things today like how hard CSS. The technology progress but people’s refusal to learn and desire to whine on the internet has stayed the same.

This is true, but the dominance of IE and its quirks, especially during the early 2000's, should not be underestimated. The browser situation, especially on Linux, was absolutely abysmal then.