I think the dislike for Bose, Monster, etc, starts with dislike of the company at large. Lifestyle/marketing-driven companies rarely make a product that provides good value for the money and often have less than respectable business practices in terms of litagatory anti-competitive behavior and marketing that just narrowly escapes "truth in advertising" laws largely by inventing non-provable scientific theories. Effectively, they prey upon their own customer's uninformed and gullible nature rather than trying to demonstrate that their product is the best option for the money.
However aside for dislike for the company, the actual audio aspects of Bose are disliked in the audio world mostly because of their loudspeakers. I haven't heard their headphones but I've heard that their noise cancelling cans may actually be the best among noise cancelling (which isn't saying much, but if you need it...) their Wave Radio is fantastic, but disastrously overpriced for what it is. II know nothing of their IEMs but I've seen enough failure reports to suspect the build quality.
But the overall hate for the Bose signature originates in their speakers. There was a signature someone used to use on another forum when I visited it years ago, a a full-size speaker forum, something to the effect of "No highs, no lows, must be Bose!" A very accurate and humorous statement.
Bose HT mini-speaker systems are effectively just small mid-range drivers, spread throughout the room. The mid-range drivers are actually of good quality. But they're too big and tuned too low to produce any accurate treble, so the highs are squarely rolled off, and they're much too small to produce bass or even mid-bass. And they lack enough mass to move enough air to show mids in a very convincing way, though they take a surprising amount of power and output surprising levels for their size. To make up for the complete lack of bass, they include a single "subwoofer" box....made of plastic. This box lacks the mass or power to produce real sub-bass. Instead it specializes in providing the midbass the satellites lack. The problem is unlike sub-bass, midbass is still directional. You can tell its coming from the box and not the speakers.
Now, they do provide something unique. They are the smallest speakers available that provide somewhat detailed sound and a wide soundstage that sounds somewhat convincing. Kudos to their designers for that. However you're still left with detailed but quiet mids, no highs, they've been rolled off at mid-treble, mid-bass that's clean but detached from the channels and very monodirectional, and zero sub-bass.
For someone who has room appearance and invisible speakers, as their chief concern they have value. But they misleadingly advertise them as the best in sound, for a high price when in fact they're a half-way sound that acts as an ok compromise for appearance for a high price.
Their "sound rooms" they demo their speakers in also feature acoustically treated rooms ideal to that specific frequency range, and the source material is hand picked and re-mastered to take advantage of the frequency output of those specific speakers, meaning normal sources you'll play at home will not sound that way, even if it's the same film/recording.
They also created a trend in the late 90's & early 2000's due to their popularity that was starting to convince the public that you don't need big speakers, small satellites and one subwoofer sound just as good. Thankfully thought the public and other audio manufacturers fell for that gimmick for a while, the fad has ended and you don't see that much anymore outside Bose which looks like an anachronism as a result. It's physically untrue. Audio is analog. Audio is the movement of air. The more air moves, the more sound there is and the more there is to work with in terms of real-life presence, and to move more air you simply need a bigger surface area. To sound realisitic the speaker must move the same amount of air as the original object would have at the same distance from you. A 3" mid-range driver can not do that across all frequencies. Thus the "satellite" must have the ability to produce the full range from mid-bass through high range at proper SPL levels without distortion. Only the sub-bass is directionless and can be detached to a dedicated sub-bass driver. With dynamic driver tech a single driver can not produce that full range at appropriate levels (headphones excluded because they must move very little air at any frequency to simulate reality since they're placed at or in the ear canal itself.) At a minimum a woofer (midrange driver) and tweeter are required. Ideally a seperate woofer (midbass) and midrange driver are used. Other techs like electrostatic panels can do it all in one. Bose sells, literally, a physical impossibility. There's nothing wrong with liking it for what it is, as long as one understand that what it is, at its selling price, is a poor value and is far from representative of the best in audio. The problem is most of their customers don't understand that and were deceived by clever marketing.
If they are to be that dishonest about their main product, it's not a stretch to believe they're being dishonest and misrepresenting the value in all their products.
Thus, they're distrusted here, by those who know the kinds of tricks they use.
If you happen to like them, great. And if you're in the market for a clock radio or noise cancelling phones, they'll even get a recommendation from many here.