Because Windows comes with a 32 bit AND a 64 bit Internet Exploder. Adobe can't change that.
The ActiveX installer puts both plug-ins on your system per Microsoft requirements.
C/Windows/System32/Macromed/Flash and C/Windows/SysWOW64/Macromed/Flash
Or, perhaps you're referring to the "Flash Player (32-bit)" in the control Panel.
THAT'S the Global Settings Manager, which IS a 32 bit application ,and again, per Microsoft requirements, it MUST be listed as a 32 bit app in the Control Panel.