It’s very common when we’re angry or resentful to lash out and say mean things. When we’re having a bad day we may do the same thing.
Being mean isn’t a nice thing to do, but it also means we may continually cross the line on our behaviour. No one should have to stand their guard, because we may say mean things.
Some of the time we may not even know we’re doing it. We should stick to what the presenting issue is and let everything else go. It’s always better to say nothing, than to say something we will later go on to regret.
To challenge someone for challenges sake, isn’t nice. Why be mean?