"Banning people based on their religion, ..."The ban is based upon country. Muslims in general aren't being banned, otherwise travelers from countries such as Indonesia would be affected. They aren't.
"...canceling visas that have already been granted, ..."
If the visa has been granted to somebody from a country to which the immigration halt is applied, or otherwise is now subject to additional background checks that were not applied when the visa was granted, then the United States Government certainly has the right to revoke or otherwise suspend the visa.
This may be rude and it may be inconvenient, but it's hardly a violation of human rights. It certainly isn't unconstitutional.
"...firing reasonable dissenters rather than working with them, ..."
That oft-quoted "one man's freedom fighter is another man's terrorist" comes to mind here. What constitutes "reasonable"? If your boss tells you to do something, you do it. Or you resign. Or you get fired.
What if your boss told you to do something illegal? At the time, your options are identical: do what you were told, resign, or get fired. In due time, if you chose one of the latter options and your boss truly was breaking the law, you will be revealed to have taken the superior moral position.
We have yet to see if that is the case anywhere. If it turns out that way, it will harm Trump. I suspect, however, that if the appropriate courts rule in Trump's favor we will either not hear of it at all or it will be dismissed as judicial activism.
"... discriminating against LGBTQ folks, ..."
The White House affirmed today (https://www.nytimes.com/2017/01/30/us/politics/obama-trump-p...) that LGBTQ protections enacted under the Obama Administration will stay in place.
"...destroying access to women's health care, ..."
Citation needed.