Yes, unfortunately. Not only is it morally acceptable, but pretty much unavoidable if meaningful change is sought to be enacted. To put it this way, if political violence was inherently "wrong", then the entire United States of America should not exist. The British did not leave our shores because we've asked nicely or protested a lot. We've tried both of these things and the response was military intervention. Nazi Germany was not defeated by strongly worded letters either (that was also tried!).
However I strongly believe violence must be proportional to the offense and follow a plan. Random riots achieve nothing. Let's not dance around the issue. The question here is if violence against the Trump administration is permissible (yet). And right now the answer is no. Because a) elections have not been abolished yet or interference has made free elections impossible or farcical, and b) Trump and his unelected sycophants are still broadly moving within the confines of "the law" as applied during a time when the US actually cared about strong checks and balances.
Grandpa certainly doesn't have a strong mandate, but he has "a" mandate to enact his political will for 4 years. That however will change dramatically if he moved against basic constitutional rights, such as now as he is trying to ban all media critical of him. The proportional and correct violent response then would be to destroy media outlets shilling for the president.