To me it seems way more difficult to learn how to write psudo html ruby code than it is to just write html and js. I feel like Rubyists are always doing everything they can so they dont have to write JS. i.e. Coffee Script, Opal, etc. lol
I don't think its about avoiding Javascript as much as it is that Rubyists just really love writing Ruby, at least its that way for me. Javascript and React pays the bills now, but I was primarily a Ruby dev for a decade and I really do miss it.