To me, it's clear this was not "because you used Firefox", albeit that was the written pretext given by the company. It's also not because they changed their mind about the React rewrite. It's far more likely they thought you were going to be a bad culture fit.
I could be wrong, as I have very limited context, so here's my justification for making that claim. You're giving a very one-sided view in the intro, and then other important details crop up below. You didn't know Angular, for example, but the company was willing to give you the time to learn it. You sounded hostile about being asked to work more in the office. Reading between the lines, it seems you were also critical about what work you were given. I'm sure you were trying to help, and you were just being honest. But that kind of feedback costs you capital that you didn't have, since you were so new and lacking in experience where they needed it.
As a manager, I can imagine thinking that you don't have much expertise in our tech stack, and you're not the most easy-going of people to work with. You mentioned that you thought you were a good fit given their technical goals. But tech skills are a small part of "fit".
I think the manager made a decision that they thought was the best for both of you, and they were probably right.
And it seems like you need to learn from that, rather than come here looking for validation that none of this was your fault.
I could be wrong, as I have very limited context, so here's my justification for making that claim. You're giving a very one-sided view in the intro, and then other important details crop up below. You didn't know Angular, for example, but the company was willing to give you the time to learn it. You sounded hostile about being asked to work more in the office. Reading between the lines, it seems you were also critical about what work you were given. I'm sure you were trying to help, and you were just being honest. But that kind of feedback costs you capital that you didn't have, since you were so new and lacking in experience where they needed it.
As a manager, I can imagine thinking that you don't have much expertise in our tech stack, and you're not the most easy-going of people to work with. You mentioned that you thought you were a good fit given their technical goals. But tech skills are a small part of "fit".
I think the manager made a decision that they thought was the best for both of you, and they were probably right.
And it seems like you need to learn from that, rather than come here looking for validation that none of this was your fault.