No, they're not really shitty, they're actually kinda cool...I just thought it might be funny [in a juvenile sort of way] to combine the two words given the context.
Found these randomly on the internet and figured if there's one thing that could cause "penis envy" it'd be wanting the freedom to piss anywhere I please...also, in urinals like these:
Only a tad Perverse
Not too sure what to think about this one.
Confucius say "glug"?
Someone's going to hell for this one.
This one i'd give to a toddler for target practice.
What's a urinal without a little sexism?