There's a page, but it redirects to virtue signalling, and the only mention on that page is "Consequently, the antonym 'vice signalling' has emerged to refer to blatant amorality.", which is not only wrong, but almost meaningless.
Here are two pages, one says you should do it, the other says you shouldn't do it.
2015 political article on it
Interesting, urban dictionary does not have an entry about it
