I agree. The level of hate and greed politics is appalling and these are the outcomes of that. Helen Comperatore, the wife of Corey, the firefighter who was shot by the shooter, has spoken publicly and said that Joe Biden contacted her and she has no ill will towards him. She added that she has not heard from Trump. I see that someone else has given detail about Corey Comperatore in another comment.
I would also note that a few months ago, that vile internet guy Alex Jones who was sued for defamation against the Sandy Hook school shooting victims, was encouraging an assassination attempt against Trump or another GOP candidate in order to rally the maga base to go out and assassinate democrats on their 'deep state' hitlist. It's appalling.
Finally, a shout out to British media. Channel 4 News ran a story about the GOP database of shooters, gun owners, gun nuts - all categorised as to their political affiliations and essentially how unstable they are. The shooters family were on the list for the area of the rally and ranked in the top 20 out of - I forget the number, but it was in the 10s of 1000s. C4 seemed to be first with this story.