It means One who has an opinion (a "take") on something.
It is probably not an established word or phrase, so the search for a meaning/definition bore no fruit.
However, here are some more examples --all rather obscure-- of actual use:
From movetoamend (I think they're saying "here's a good opinion...")
the best take haver:
I’m no one. I don’t want to be anyone. I just want to see the ruling class overthrown and punished.
From metaphoricalmoose (I'm uncertain what was meant.)
the good take-haver:
what if we kissed at the neighborhood high voltage box
From shitliberalssay (This one is sarcastic.)
The Good Take Haver has logged on
From twtext (If there good ones, then, surely, bad ones too.)
N. Bourbaki, Bad Take Haver:
WARNING: extremely nerdy thread incoming.
I conclude that it is still a very obscure word/phrase but, perhaps with help from Mother Jones herself, it will become an established one, albeit confusing (or annoying) to some ears.