Have you reported this to the Wayland folks? Is there a reason to keep it here? It seems like even if Steam is doing something incredibly bad it's up to xwayland to not die (as evidenced by the fact that regular X servers don't).
Its fixed now but you also have to remove runtime libraries
rm ~/.local/share/Steam/ubuntu12_32/steam-runtime/i386/usr/lib/i386-linux-gnu/libstdc++.so.6
rm ~/.local/share/Steam/ubuntu12_32/steam-runtime/i386/lib/i386-linux-gnu/libgcc_s.so.1
rm ~/.local/share/Steam/ubuntu12_32/steam-runtime/amd64/lib/x86_64-linux-gnu/libgcc_s.so.1
rm ~/.local/share/Steam/ubuntu12_32/steam-runtime/amd64/usr/lib/x86_64-linux-gnu/libstdc++.so.6
rm ~/.local/share/Steam/ubuntu12_32/steam-runtime/i386/usr/lib/i386-linux-gnu/libxcb.so.1
OK, that Steam runtime compatibility issue has come up in several ways.
Hello @waitwhobrokethat, the steam client was adjusted to prefer system libraries over the steam runtime variants by default and shouldn't encounter a Xwayland specific issue anymore.
Closing.
Nothing extracted yet.
Steam For Linux Crashes Xwayland or Can't Find a Xwindow With Xwayland in Fedora 21