Speaking of the Constitution: If we can limit the number of rounds in a firearm magazine, we can limit the number of pages in a Hustler magazine. The same specious utilitarian logic that applies to the first also applies to the second.
...we can limit the days on which non-whites are free and can enjoy "low capacity" civil rights.
...we can limit the number of times women can vote.
...we can tax Qurans to limit their distribution.
...we can require Mosques to get a "permit" for "hi-capacity" morning prayers.
...we can limit the number of gay couples a church can marry.
...we can limit the number of abortions a woman can have.
...we can make Citizens get a "Privacy Permit" in order to exercise their 4th Amendment Rights.
etcetora, etcetora, etcetora.
NONE of these the Left would ever dare endorse. It's always the 2nd Amendment they attack with zeal.