Send a short message to a monk who broke the precepts, say something unpleasant and call him a "sinner". Excuse me, am I wrong? What is the cause and effect?

If you do see that he has violated the fundamental sin in the precepts (although we can't see the monk's precepts, some of them are fundamental, just like the Five Commandments or the Ten Commandments, such as killing, fornication, stealing and lying. ), then, for the protection of Buddhism, you can tell the monks about it. If monks keep staying in the group of monks (for example, some temples are purely monks), then if you have hatred or anger in your heart, then this is not good. As for cause and effect, this should be based on the ten evils, even the evil words in the ten evils bring anger. According to the size of your anger and the length of time, I suggest you confess to the pure monk. If there is no monk, repent in front of the Buddha and never do it again.