It's jargon/buzzwords. I won't say this is poor grammar (though it is) because it is really a new style. While I will go to my grave saying it is wrong, this will be in Merriam Webster in not too long. You will hear "show up to" used a lot both in the African American community of millennial age, and among people who talk about emotions. To me its up there with "my truth", "speaking truth to power", "my authentic self" in terms of it being basically buzzwords.
Because it is a buzz word (phrase) it is hard to define, it will be used in many ways and there is not a real definition so it will be misused (if that is possible). The way it is being used here is "recognize and validate". It's like saying "I see you".
Currently, there is a big push by some people (trying to keep this apolitical) for everyone to agree that we all need to be validated. We all need people to see us for who we are, and say "I see you, I respect you, I love you". (note, I am not trying to "invalidate" anyone's existence, so please no responses about that).
I believe this particular phrase probably came from "show up for". As in "if you are in trouble, I will show up [for you] in your time of need", and it just got mangled from there.