The 32bit libraries haven't been included in the 64bit build since ... as long as I can remember. Some time before 10.10 anyway. People seem to expect it them to be since they are in Windows, I think, but ... this ain't Windows. With Linux a 64bit OS really is a 64bit OS, not a 64bit and 32bit and 16bit OS.
Just for the record, I've fallen for it before more than once so I'm not being elitist in any way, it's just how the thing is.