Friend said they were going vegan after our eye opening talks, now I find out they went back to eating meat

I am so tired and heartbroken. This is a dear friend of mine and fellow autistic queer buddy that I had some friction with after they ordered chicken when we were out together.

It caught me by surprise because we are new ish friends and everytime we were out together before they ate vegan. So I just assumed they were as well, since I talk about animal liberation and speciesism and veganism quite all of the time.

After the chicken incident we had a talk and I shared how my life purpose is around animal liberation and most of what I do (I am a musician) is around that and themes of speciesim and education on the matter and so on. I never pushed for them to be vegan, it was mostly asking them to never put me in the position of having to witness severed animal parts at the dinner table.

After a while they sent me a vocal message in which they said that our talks had enlightened them and that they are now trying to be vegan and all these things. I was so happy I started crying and said that I am there to help in any way needed.

Fast forward to NOW: I learn they tried this for like a couple of weeks (maybe 2) and now they went back to eating meat. They did not tell me, they told another common friend.

I am super upset. Why bother telling me you are going vegan at all? Just don't get my hopes up and make me trust you and then take your promises back. I am also super hurt because I considered them a safe person which now I have trouble seeing as such.