Imagine you're in a classroom setting, and you notice someone is listening to music with noise cancelling headphones during work time when everyone is being loud, they also get to take tests at home on their own time, and they also turn in their homework pretty much whenever they want. You see this and think that would be awesome for you, but you shrug it off and go back to doing your work in the same loud environment.
What you don't see is that the noise from everyone being loud during work time makes it impossible for that person to concentrate, and can even bring them crippling anxiety; they get so anxious about taking that test in only an hour that they get physically ill and being in a home setting helps calm their nerves; their mental health is so crippling that they don't get their work done in time, but they want to, it's not their fault that their anxiety is crippling, so they are accommodated.
That person went through countless doctor's appointments to get a diagnosis, enduring strange and sometimes abusive treatment, constant tests and misunderstanding, and before that they were constantly in emotional stress, experiencing meltdowns, and severe anxiety, because they didn't know what was happening or how to fix it.
Then they meet someone who they think has experienced something similar, because you want those accommodations, and went out of your way to fake having a disability; or you make up a new one entirely; and think "you don't actually know that I am faking, so you have to believe me".
That person was excited to meet a friend who they could talk to about this stuff, but when they talk they find out, oh wait, you don't have crippling anxiety. . . You don't get sensory overload to the point where you pass out. . . You don't actually have any embarrassing accidents that you couldn't control and you're so glad you were wearing a diaper at the time. . . it's all a lie that you're trying to rationalize simply so that you can get that ez life that the other person had to break their heart and back to get. . . And the worst part is, even with those accommodations, that person's life still isn't and will never be easy. . . While yours is.
Wear a diaper all you want, but don't you dare try and tell someone you're disabled or convince anyone that you need them when you absolutely don't. Obviously, telling them you're disabled is a lot less cringe than telling them you're getting your jollies out of it; but that person will then see you as the person I described above and you don't deserve that. You didn't go through hell for it like that person did. You aren't crippled by your environment and need accommodations like they do.
Don't forget at the end of the day, you're a person deciding to wear a diaper and NOT someone who needs them. I'm not trying to kink shame, I'm literally someone who is wanting to wear a diaper 24/7 (and might be getting there soon with my new job!) for my own personal reasons, but we still MUST have massive respect for those who do need them. We and the disabled are NOT the same and don't deserve the same treatment.