I disagree with the idea that this is a "popular" or "overused" utterance, on a wide basis. But as to its meaning . . .
You are no good as a man (a failure as a man), and your mother is unwomanly (somehow mannish).
You are inferior as a man and your mother is inferior as a woman.
It is an insult that implies that its target fails to meet stereotypical gender role prescriptions for masculinity. The reference to the target's mother most likely usually implies that she is also not stereotypically feminine (that she is "mannish" in some way).
Logically, it could be that the reference to a woman is at least sometimes not meant (or not interpreted to mean) anything special about the mother, but simply that the target falls so short of "being a man" that they are compared not even to another man but to a non-man.
This likely relates to, or may perhaps be mistaken for You'll never be half the man your mother is and variations on it.
That, in turn, seems a twist on more common expressions similar to (someone) isn't/wasn't/will never be half the man [someone] is/was.
It's unclear to me whether the original comparison related particularly to the idea of a masculine gender role or if man merely symbolized person, or both.
A cursory online search reveals references beginning in 2011.
There are also some examples of "Yo mama" type maternal insult jokes:
You Think You Strong? You'll Never Be Half The Man Yo Mama Was!
The song "Hurts to Think" by American singer-songwriter Miranda Lambert (2011) contains the line: You'll never be half the man your momma is.