Most languages had major design flaws. Rubyists will gladly complain about how OO is bolted on in Python, Python users will gladly talk about how slow Ruby's interpreter was and how god awfully complex the syntax is. Both of them have limitations in their runtimes and are actually catching up to JS in some areas (see Python's adoption of async).
We can talk about how baroque CL is or how much Java sucked in 1995, how massively complex C++ is, etc, etc. Those arguments have been made for decades, though. JS is no worse than most languages in various ways, but people are pissed off because their chosen language isn't as popular.
Maybe that's a cynical point of view, but these criticisms never get past the most superficial concerns, so it's not obvious why people really care so much.