Needless Anxiety

A lot of my anxiety over the past few months has been caused by others being inconsiderate. Not responding to messages, not even acknowledging messages, etc. etc. As someone who is always prompt in replying to messages, I have long realized that most people are not wired that way. But, surely, that cannot be a blanket excuse for inconsiderate behaviour? I wish I was able to say "If you don't care, I don't care" instead of working myself up into a ball of stress over things that are not in my hands. I realise that everyone has been through hell these past few months. No one has any surplus compassion--compassion fatigue is a thing. But I am not even looking for compassion, just a minimum level of professionalism. I suppose even that is too much to expect. Why are people such mugs?