Because 'Breadtube' is a controversial term, let's talk instead about the behaviors and trends people are criticising when they say it, as best I can guess:
Money
Brands
Individualism
Lack of radicalism
Dilution

Money: Obviously money can be used to purchase goods and services and its better than peanuts, nobody has an issue with earning money for your work, it's the stuff surrounding the money that people are concerned about, such as...

Brands: A lot of the success that comes with money is linked with a surge in brandifying yourself, what that can do is make you biased, egotistic, insincere, untransparent etc. Those are genuine things that need addressing...

The whole damn reason people care so much about this is because it's political youtube, nobody's annoyed with cr1tikal or Jenna Marbles making lots are they?
One might say you have a larger responsibility when you're political.

I mean come on, if you don't think money and brands might shadow your opinion or make you less interested in a certain cause over money and fame I think you're kidding yourself.

I mean to just name one, Contra's financials and status have arguably soured her outward points. She once even boasted about how she was rich and successful.
If you consider her current leftwing, then that and other statements from her might sound a bit eyebrow raising.

Individualism: Many are now choosing to say that nobody can be held responsible because they're all just indi creators doing their own thing, that it's actually all just art now and not PoliticoEd, therefore any calls for responsibility can be ignored. This isn't a great take.

Fandoms and movements form around shared topics organically, a collective if you will, and even though you might not like that, that's what the platform does and we have no choice but to deal with that, not deny it.
Remember, the 'skeptics' also denied being a movement.

If there wasn't a movement so to speak, why are there certain people now who genuinely set off to become leftist youtubers? Instead of organically developing over time based on years of real life experience?
Don't just discover your inner Libertarian whenever it best suits you.

Lack of radicalism: people making these points tend to be further to the left than most, and thereby when you hear of a YouTube current that represents you only to see something that's a little sub par for your liking, you can get a little frustrated.

If you hear about democratically elected presidents getting overthrown, or settler states genociding minorities, but see little talk of this by the most popular folks yet do see plugs to patreon you might get a little confused.

Many folks like me wanted to educate and agitate for a revolution but now find ourselves in a sitch where we find many of the biggest voices are just wrong and people should be challenged, but our reach wasn't as large. This leads me to...

Dilution: By this I mean when creators dilute their content to make it appeal to a broader audience.
Criticism of this normally always has the same response "Oh what so you want to make our videos more boring!?"
Nobody, NOBODY, is saying that.

There is no binary here. You realise you can make great videos that are also sincere and not overindulgent and flanderised right? The criticism is that said 'broadists' get the lions share of fandom and with it the most influence.

You might argue "But you can bring them over to you" but often this just isn't the case and with the added trends of Brandification, it just leads to stanning said people instead of expanding their horizons. So in other words a sort of cult following emerges.

And that following might I add is not suddenly solved by just denouncing it or elements of it.
That's called Lampshading.

The whole reason ofcourse why there's such drama is because we unlike the right have no formal structure, no financial backers, no formal leaders, no politicians or political parties of any significance in power. So stuff like left tube is all we have, so we care about it.

I try not to blame any creator for suffering some of these things, even I did when I was around, what matters is to take steps to solve it.
As you can see there's a tonne of interconnecting issues here and it's super messy.

If you ask me, probably best for you all to get involved in real life orgs, parties, and unions. That way we can at least tell our comrades apart from 'the man'.
YouTube might not be the best place to devote all your time and effort, especially with all the shit in the world RN.

And yes and read Tyranny of Structurelessness, it's a short read that defo solved some of the issues plaguing some of the groups I've been in.