Two issues. The question is what was your intent. Proving that it was sent with the intent of causing distress or anxiety is much harder in that case. For example I don’t know a single vegan who would react with distress or anxiety to the image of a steak. That is just nonsense. They would just say “yuck”.
But if from the circumstances it is clear that that is the intent, perhaps because the vegan in question repeatedly expresses distress and the accused in question still keeps sending them then why would we not punish that? As in do you want that kind of behaviour in your society?
That was issue one. Issue two is about the 5 years. You say that as if that is the standard length of punishment a first time vegan abuser should expect. In reality this person has previously been convicted of a sexual crime and then commited infractions against multiple people. Surely these factors played a role in the lenght of prison sentence he received?