Edit: Reading the comments, I realize how flawed my attempt at being rational was. This issue is so much more complex than I originally thought and I didn‘t realise how much more there is to it than just: „The term diff isn‘t toxic by definition, therefore typing diff isn‘t toxic“. I was hyper-fixating on the wrong things and failed to see the bigger picture; keep that in mind when reading the following nonsense. 
(I would love to delete what I initially wrote, since I realised how wrong I was, but I think it sparked some interesting responses that are worth reading, which is why i‘m going to leave it as is.)
I want to start by saying that I don‘t use the term „diff“ often and if I do use it, I mostly do so jokingly. I also don‘t care if the term gets banned or censored (like gg ez); I really couldn‘t care less if the term „diff“ gets censored and my problem is mainly that people say that using „diff“ is toxic, because it really isn‘t and pretending that it is and saying that it should be a banworthy offense could lead us down a dangerous path of banning everyone and everything we personally don‘t like. I am simply trying to bring some objectivity in this discussion by bringing up the definition of „toxic“ and seeing if it applies to the term „diff“, so please don‘t make an argument by taking the moral high ground and pretending that I‘m just defending toxic people because I want to be toxic myself because that isn‘t helping anyone.
Now, according to the Cambridge Dictionary, „toxic“ (used informally) means:
a) very unpleasant or unacceptable
b) causing you a lot of harm and unhappiness over a long period of time
With this definition in mind, I don‘t see how simply saying „diff“ could be considered toxic.
Is it unnecessarily rude? Yes.
Does it cause you a lot of harm and unhappiness over a long period of time or is very unpleasant or unacceptable? No.
Should being „unnecessarily rude“ get compared to being toxic or being abusive in chat and therefore be a reportable offense? NO.
You being annoyed by something someone says in the game is NOT abusive chat. Being abusive is inheretly toxic and saying „diff“ is not toxic by definition. You are NOT being harmed over a long period of time and it is not unacceptable. I’d support censoring the term „diff“ to protect people who are easily offended, but I do not agree with the sentiment that people wo use the term „diff“ are toxic and therefore should be banned.
I created this topic because I think that the term „diff“ is a problem. Not because it is toxic and people who use it should be banned, but because there is a group of people that truly thinks it is toxic and use it as an excuse to be toxic towards other people themselves and because there is another group of people that thinks people are just being „too sensitive“.
Let me also add that reporting people who simply use the term „diff“ causes actual toxic behaviour to go unnoticed because they‘re being flooded with reports of people who just used the term „diff“. I also want to add that you‘re not justified to be toxic or aren’t toxic just because the term „diff“ isn‘t toxic. You can still be toxic or abusive by missusing terms such as „diff“. Not everyone who uses the term is toxic and people can be toxic by responding to this term in a harmful way, context matters.