This argument substitutes the observation that something happens routinely as a reason for it to be right.
this argument mus be evaluated, because its pattern is actually quite valid if there is no relevant difference between compared behaviors.
In many ways, this is similar to appeal to popularity, but is slightly different in that the event in question is not claimed to be popular - just common
It is also similar to bandwagon
Director Jones is in charge of running a state waste management program. When it is found that the program is rife with corruption, Jones says: "This program has its problems, but nothing goes on in this program that doesnŐt go on in all state programs."
Yeah, I know some people say that cheating on tests is wrong. But we all know that everyone does it, so itŐs okay.
Sure, some people buy into that equality crap. However, we know that everyone pays women less then men. ItŐs okay, too. Since everyone does it, it canŐt really be wrong.
There is nothing wrong with requiring multicultural classes, even at the expense of core subjects. After all, all of the universities and colleges are pushing multiculturalism.