Why does sql configuration manager show 32 and 64 bit options when only 64 bit version is installed?
Because you could potentially have some old 32 bit instance on that computer. The config manager tool is designed to allow you to configure instance of that version and lower.
One could argue that the tool shouldn't show that node if there isn't any 32 bit instances on that computer, but that would be a wish for MS to do: https://feedback.azure.com/forums/908035-sql-server