Don't defend those people. Don't compare to other groups. Don't do it. That's what they want. Antifa is a different thing in kind to even Nazis. Nazis are worse, don't get me wrong, but Nazi's are pretty in your face about it. Antifa's methods are to make you fight for them. Yes, true, they aren't killing people. But that isn't because they've taken a moral stance. It's because the Antifa method is to show up to other people's marches or protests, raise the tension, start a scuffle, and then hope other groups kill each other.
Antifa is a bunch of communists. They wan't a violent revolution. Remember the argument not long ago about accelerationism, and people saying they'd rather Trump in office because it will destroy the system faster? That. That's what they're doing. They go to right-wing protests, left-wing protests, civil rights demonstrations, anything with a chance of political tension. They go masked and armed because they want people to be afraid and stupid. They shout and spit and hope to start a riot. They do property damage and fist fighting at other people's demonstrations to drag the police in, and then hope for the police to conflict with innocent protesters, and then put that up as propaganda to villify the nation as a whole. They're trying to make the country worse on purpose in the hopes a militant revolution happens.
You and I may disagree on things, on what the causes of and solutions to our nation's problems are, but we both want to build a better society. Don't be tricked into defending people who are trying to tear things down. That's what they're trying to do. Antifa doesn't want to kill people themselves, that's not the purpose of their activities. The purpose is to drive other people to violence until society as we know it falls apart.
The death of George Floyd is bad, I don't mean to suggest otherwise. But moving forward from that, if as a nation we supported the peaceful demonstrations and had a dialogue about meaningful reform and we progressed, that would be a blessing out of the tragedy for almost everyone. For the nation, for the black community, for every community, for liberals and progressives and conservatives. It would be good for everyone... except the revolutionary communists who actively want us to fall to pieces. That's why antifa goes out to break things, because they don't want progress, they don't want peaceful dialogue, they want riots, and they want regular people to think riots are better than peace. Don't fall for it. They're using you.