Rhaegar was more responsible than the Mad King ever was for the countless who died during Robert's Rebellion, including members of his own family(which he set aside). Even Viserys and his pregnant mother narrowly escaped with their lives.
I don't know if I can blame Lyanna, though she doesn't get a full pass.
If she wasn't aware of the damage her and Rhaegar was causing than she was being wilfully ignorant.
I find it hard to believe she has no idea that Rickard and Brandon were killed, with Eddard soon following them if things were different.
I don't believe Rhaegar loved Lyanna as much as he was infatuated with her, he wanted a union of Ice and Fire and he probably knew the cost.
Jon Snow choosing to keep the name "Snow" would be the biggest "Fuck you" to Rhaegar, I'd personally enjoy that but I suppose it'll go a different direction.
It's still possible Robert could have acted deceptively as well. Like Lyanna actually told him
she would not marry him, despite what their fathers had arranged, and that she loved Rhaegar, and Robert made some kind of threat like he'd turn House Baratheon on the Starks for dishonoring the betrothal or something, and so Rhaegar actually fled with her.
Or Robert was so broken by learning she did not love him back, loved Rhaegar instead, and he became all consumed with bringing Rhaegar down, and conspired to do so.
I mean all the show has told us is that Brandon Stark got word of Rhaegar abducting Lyanna and rode to KL, the stupid Mad King arrested him, and then Rickon Stark went to get him and they both got executed and the rebellion was officially on.
There's a lot of plot wiggle room around the details of the abduction and who notified Brandon Stark.
