Almost any credible values the Aliens could have would make them want to destroy all life on earth. And these values are probably different than most human values.
Detecting an advanced alien civilization would increase our understanding of what technologies are feasibly possible and help guide our own scientific development.
It is dangerous to have physical contact because there will be diseases on other planets but finding aliens is good the species of both our worlds can leave each other alone. So we do not wipe each other out with diseases.
Morals and working together ensured the survival of humans, so why would aliens not have any morals? You cannot assume that aliens will not have morals.
If Aliens are similar to us. They too have bad actors and a culture which endorses war for gain.
If aliens are not similar to us they could disrupt our way of life to the point of changing what human society is. This could be a good thing but it could also be worse than what we have now.
caledeon
