OK, I can see you know nothing about this. You "heard some things" maybe?

And you are blaming a guitarist for the bad choices of some people?

You sure you are not the monster?

Nobody is perfect, but lets at least be real:

• bad things can happen at concerts, this is nothing new. Famously though, deadheads had less violence and less drunken incidents than other concerts (worth noting that the fans set aside an area that was marked with yellow balloons as a support group to help people who wanted to remain sober. It was was never looked down on to not do drugs at all).
• the summer of love anniversary of 1987 brought a HUGE number of people into the scene that were only their to party and made things much less manageable. That was not Jerry's fault, they simply had a hit song and the news was mentioning 60's nostalgia daily.
• Jerry thought that music should be free
• Jerry thought that price should never keep a person out, and the band worked hard to keep prices low and play more to make up for it
• To that end, they set up their own ticket sales, and tried to fairly distribute tickets via mail to keep prices down
• Equal Pay: they paid every member equally. Jerry was very adamant about this. The crew, ticket office, band members, all must be paid the same and well. Ironically this would be a problem, as Jerry stopping playing meant people would go hungry, leaving little time to deal with himself.
• Jerry believed in business by consensus
• Famously, Jerry was concerned about how his words might be taken by the few that were a bit "cultish", so he rarely spoke to the crowd during the last decade.

They rarely traveled the world by the way, a couple of tours to Europe, and once to Egypt. That is it.

Jerry said there must be many ways to have success, and money and fame are not it. The one thing about him, more than anything else, was not trying to control people or tell them what to do.

I mentioned Elizabeth Cotten, because when Jerry found out she was struggling with bills at the end of her life, he put a song on their live record by her so she could get the royalties.

I don't know why you think this is monstrous behaviour.

people who flock to and follow a psychedelic fueled jam band for decades are sad

So you just judge people? That seems more sad. By the way, not a jam band. Dance band, but whatever. When it was a smaller group, seeing friends and family all over the US was actually fun. If it isn't for you, then nobody is making you go. This was mostly over by 1985, and officially over by 1995, so this is a LONG time ago.

and probably became trumpers.

Unfortunately some did. Which is weird, because a HUGE part of the draw to go to shows for a lot of people was being accepted for who ever they are.

EDIT: I should also add that one of the two bands lyricists (John Barlow - perhaps you heard of him) said before he died that Trump was toxic asshole, and thorough creep in 2016. Jerry of course was long dead, but the band itself has been against this bullshit for a long time.

EDIT2: Since you don't know much about this, I will add this from a scholarly publication:

"Deadheads often speak of being attracted to deadhead culture because the community is peaceful, values camaraderie and shares resources which offers a refreshing escape from the dominant culture’s individualism, materialism and competition. Pearson (1987) argues that among younger generations of deadheads, the Grateful Dead’s music is an attractive alternative to the formulaic top 40 hits of the mainstream music industry. In other words, Deadheads feel that music should be free emotional expression and should not be inspired purely by a desire for profitability.

Do you find that monstrous too?