That again is more about the disabled person's perception rather than anything based in reality. Needing a seat more than me is not "weak" or "inferior", and if they think it is then they need to work through those feelings.
Self esteem is about accepting yourself and accepting your own limitations, but accepting that those limitations do not define you. One may not be able to stand on a swaying crowded bus, but that doesn't mean one is sub-human.
I use the tube, which is what I'm basing my experience on, and there are frequently people who are clearly struggling to stand up in the crowds- these can be disabled people, people with young children, pregnant people. I don't think it inappropriate to see if they would prefer to sit down.
And those aren't the sort of people I'd object to offering a seat to. It's when people offer a woman a seat because it's 'chivalrous' that I'm sceptical. At best it's patronising, at worst it's self-righteous as well.
However, you can't just say that it's someone's fault for feeling a particular way about something. Telling someone that they shouldn't be upset about someone is about as useless as telling someone their broken arm should just get on and heal itself; it might sound like a leap of logic, but all it leads to is people suppressing their emotions rather than changing how they actually feel about things. We all need to accept our limitations, and I don't doubt that many people with disabilities do so, but what they don't like is being constantly reminded of them. If they're being offered a seat because they're a woman, then it really is an implicit way of saying that "you're a woman and therefore less able than I am", which I don't think any of us would agree with.
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I'm sure it's not what you mean to say and I apologise if I've got you wrong, but the feeling I get from you is that the only thing you would see as acceptable is not offering seats to someone who may need, in case it gives the indication that they may need them! It's all well and good waiting for someone to ask for a seat but having worked as a sports coached for disabled athletes, I've found many people with disabilities to be shy and unlikely to ask for assistance.
As a sports coach the best course of action is to assess someone's needs and suggest politely how an environment or situation can be adapted to better cater for them, be it offering a lighter discus and something or hold as a support when throwing, or offering a seat to them on a train.
I'm not sure that's far from the truth, but one thing I've noticed is that the last thing people with disabilities or things that "aren't normal" is to be reminded of that. It's very circumstantial, though, and I imagine much of it comes from how it's worded. If you prephrase it with "I'm getting off soon, so please have my seat", or even just get up without saying a word when they're the closest person, that's probably fine. If you make it obvious that it's simply because they have a disability/they're a woman/they're somehow different to you, that's probably not acceptable.
I think there's a difference between those with permanent disabilities and those with temporary ones, too, for a number of reasons.