You don't have to look very hard to find some vitriol toward SAFe within the agile/Scrum community. I have my problems with SAFe (mostly Scaled Agile Inc. really) myself. I've never understood the venom directed at SAFe though.
I do remember having some antipathy toward Scrum when I first learned about it. My feelings toward Scrum are complex, much of which has to do with my preferences and personality, but it took some time to work that out. (I see its value these days.)
I think both cases had a common underlying issue however.
People tend to see a framework as a complete end state to implement. How you react to that depends heavily on where you're coming from.
If you've already internalized the agile mindset and principles, a framework like SAFe is going to look very regressive. There are significant elements of it that will feel like major steps backward, that feel less agile than what you're currently doing. In some important ways, you'd be right.
If you're just starting your agile journey, you view that same framework very differently. You see that framework as current best practice that, once implemented, will solve all of your problems. You see significant improvements over the way you're currently working (which generally includes no clear priorities, no dedicated teams, and no alignment). In some important ways, you'd be right.
Everyone would be better served viewing any proposed framework as a potential next state. Would adopting this framework, or elements of it, get us closer to our goal than we are today? Is it a reasonable place we can get to next, that we can then build off of to get to a new, better next state? If the answer is yes, the framework is something worth looking into. If not, then the framework isn't for you. If it isn't helpful to you, consider that it could be helpful to someone else.
If you view a framework as a potential end state, all you'll see are its flaws. If you view it instead as a potential next state, you'll see its virtues.