@Pogre At the law stands today, Twitter/Facebook/Insta/Reddit are commercial entities - Free Speech doesn't apply to these. Maybe it should, maybe it doesn't. Free speech guarantees her right to speak his/her mind in a public place and not be prosecuted for such. Again, this doesn't apply to postings on internet boards.
Gina and Pedro are still free to call TV press conferences and express their opinions.
As for reasons for firing - these should a)
apply equally to everyone and (while I didn't check your source) seems like there isn't the case. BUT employment "rights" in the USA are
at will. Exactly that it says - Company could easily fire you for violating their policy (did you read in full your current employment contract and employee handbook? I bet Disney's one is longer than most for obvious reasons)