Anyone wondering about Wolverine's popularity has to do it through the lens of the readership and the stories from decades ago, not now and not in todays language.

What I will add is that, as someone who was not a Wolverine fan by any means (Cyclops for life) but I sure did like doing sketches of Wolverine. He was always one of the best characters to see in action. Everyone else was rather still, shooting from range while standing, moving things with their minds while standing, but Wolverine had to get in close and take the hits, so not only is he a character that at the time had so much potential for a writer to work with he was great for artists to go crazy with too.