When it's blatant, incontrovertible, and repeated lying- yes, that's pretty much my standard.
Just as a reminder,
here was his response to the scandal before he was completely outed. We're not talking about differing interpretations, or political spinning- this was bald faced lying to the public. If that's acceptable to you, great. But I'll always support their resignations in cases like this.
In this case, I think Weiner is finished regardless of whether he's man enough to resign with some semblance of dignity. Breitbart claims to have an X-rated photo of Weiner Jr, and Weiner has said that he can't say for sure all the girls he has cybered were of age. Ugh.