I have read parts of his book all the way through ...
Let's look at two examples I remember - Dog walkers (washers?) and corporate lawyers.
As I understand it Bullshit jobs are those that exist to serve the elite who otherwise "should" do the work themselves (dog washers), or jobs that have no labour-force power and so cannot improve their lot through collective action (which can range from air traffic control to uber drivers and ... dog washers). Finally there is some kind of self-aware bullshit job that is the corporate lawyer.
There are two issues at play here - a moral judgement and a power judgement.
The moral judgement is aimed at dog walkers (or washers?). This is a job that "should" not exist - people should take care of their own pets. Well maybe.
They also have a power issue - who has heard of a dog walker strike?
The dog walker fills a space in the ecosystem - mother nature has so many examples of non intuitive niches that we should not leap to claim this one is bad.
Corporate lawyer - this is more likely a bullshit job - it exists because humans created the law, so it exists as the very definition of government regulation and interference.
But most of the bullshit about it is not legal, but the tournament set up to go from newbie lawyer to partner which drives a lot of the soul destroying ness, simply to clear the field. And yes it is soul destroying to have to justify the unjustifiable- something i suspect corporate lawyers spend a lot of time doing.
But that is again a moral judgement- yes it is bad that corporations break the law and people in bullshit jobs have to help them get away with it. But that is a different failure of regulation.
I think his view is extremely negative - that these jobs were created / kept around to serve the implied result rather than an underlying failure. The airline baggage example is a good one. Getting millions of pieces of luggage to the right place at the right time is fundamentally hard - and claiming that the solution is to "fix it" then get rid of stewardesses of whatever is disingenuous.
It's not impossible to remove bullshit jobs - automation promises to remove many, which is I guess Graber point and mine. My view is that the jobs continue to exist not because the elites deem it nice to have flunkies (I mean they do but they employ those directly) it that fixing the ecosystem that supports these bullshit jobs takes a long time to fix. It is likely that smaller new companies will simply not hire to bullshit poisitions. But given that Amazon has now reached what 1M employees I suspect some bullshit has slipped in there.
Plus there seems to be a confluence in your comment between HFT and bullshit jobs. I am sure there are socially net negative or socially net neutral jobs (HFT is arguably positive but whatever), but that's different to bullshit jobs (as I understand it)
A job that is net negative has always been a problem - is the guy making Drones in a factory knowing they will be sold to evil regimes a net negative? It may be but I don't think that sits as a bullshit job.
So there is a difference between jobs that are "created" simply to give the middle class something to do (Graber view, not mine), jobs that exist because they have not been automated yet (my view, maybe Grabers) and jobs that are socially net negative (this depends on your politics as to what is net negative)
In short the psychological harm of bullshit jobs depends much more on the employees perception of its value than some objective measure. Especially as that objective measure is so hard to come by.
In short - net negative jobs are not bullshit because choosing the externality is hard / social decision (ie the boss of shell is unlikely to have a bullshit job, even if it is net negative)
And bullshit jobs are rarely created just to lord it over people - the truly elite just hire someone to loo after their dogs / horses. The sub-elite get it created as part of the market.
Edit: running out of time - this is an interesting area but I have reached th limit for a comment
You should read about Graeber's work, it's interesting https://en.m.wikipedia.org/wiki/Bullshit_Jobs