Because a) you've probably presented the situation in the highly selective way you started off here (and listened to them in the selective way you respond to the people saying what you want to hear) and b) EASS is not an advisory body, it is an information helpline that specifically states that it cannot provide legal advice.
They have not given you legal advice, they have given you information.
The information and support provided by the service is not the same as legal advice, which should only be provided by, or under the supervision of, professionally qualified lawyers. We recommend you consult a lawyer if you want legal advice, wish to take formal legal action or want advice on the merits of your case.
All they do is provide information on how a situation may relate to aspects of the EA, they don't advise on the merits of the situation or how wise it is for you to take a particular course of action.
The EASS helpline is able to provide free advice and information about the Equality Act 2010 and the Human Rights Act 1998. We can advise you on identifying the correct protected characteristic, the sector and the prohibited conduct which applies to your circumstances.
Of course, this thread isn't legal advice either. It's entirely your prerogative to try and argue the reasonable adjustments point, but the key word in that phrase is "reasonable".
If you had taken actual legal advice they would have made clear to you that you can lawfully be dismissed due to disability, and had a discussion with you about whether it's in your best interests to keep having this fight or negotiate an exit.
I think you would benefit from legal advice.
www.citizensadvice.org.uk/law-and-courts/legal-system/finding-free-or-affordable-legal-help/