AITA for telling a colleague their disability is not a free pass to be an asshole and getting them suspended?

I (29m) have started a new position at the beginning of November with a decent sized law firm in my city

Things have been going great up until this week. The first 3 weeks I have been here I have heard lots of horror stories around a member of the office we will call J. I've heard that the last 2 people that took this position were basically bullied out of the post by J and that anybody who makes any complaints to HR basically get told to put up and shut up for two reasons. Firstly J, despite not being the most popular person in the office, is very good at what she does to the point the company sees her as invaluable and secondly, J is a wheelchair user and is apparently very quick to throw the discrimination card around as soon as something doesn't go her way.

Another key point to this tale is that I use a stoma bag and have done since I was a baby.

Anyway this week is the first week I have interacted with J as she was on annual leave for my first 3 weeks with the company. I was using the disabled bathroom to empty my bag when I started hearing a loud banging on the door. I said one moment and opened the door to a lady in a wheelchair, the infamous J. I was berated for about 5 minutes things such as "why is a healthy young man using a disabled bathroom I should be ashamed, etc" drawing the attention of everyone in the nearby vicinity before she even let me speak. I eventually got a word in, reminded her that not all disabilities are blatantly obvious and lifted my shirt up to show her my bag. She went bright red and I got on with my day.

The next day I go to use the disabled bathroom to find a poster on the door saying "wheelchair users only".I didn't make a huge fuss but happened to mention to the colleague across the table from me "have you seen J's latest stunt". This is the woman who told me to watch out for J initially

I go home for the day and return the next to an email saying to report to HR as soon as I clock in. I get in there to be told that I am receiving a verbal warning as my "tittle-tattle" in the office caused a huge bust up between J and my mentor.J was in the office and smirking all the while. I lost my cool and told J that the only reason she is still in a job is because of how long she had been with the business and that she isn't going to bully me out of my position like she had my 2 predecessors. I also told her that I apologise that she has been dealt a bad hand but that it doesn't give her the right to treat people like shit and that she is no longer the only disabled person in the office so she isn't going to keep getting away with her stunts.

I then told HR about the bathroom incident and what followed. Eventually J was suspended pending investigation

I must admit I felt great on the day but as the week has gone on I can't help but feel guilty. I wanted to teach her a bit of a lesson not put her job at risk in times like we are having (cost of living crisis, etc).

So AITA?

Update for those that are interested

Nothing official has happened but had a chat with HR strictly off the record. J was suspended as we had offsite visitors in on the day meaning that her sign could have been deemed as bringing the company into disrepute which is classed as gross misconduct. I said off the record that I'd be happy to drop the complaint as tbh I don't really want to play the office politics and im already over what was said. I also harbour no ill will towards the company as they have been fantastic with me and i cant blame an entire company for the unauthorised actions of one person. However, its being taken out of my hands as the venue director is getting involved which strikes me as a bad sign for J. For those interested they as expunged my warning so I have a clean slate again.

Whilst nobody is openly celebrating Js departure as would be a bit classless there certainly seems to be a better atmosphere around the office so I guess that's a positive.

Just wanted to say thanks for the love and support on this. Just shows what a wholesome group the people here are. Take care all