"Peace Officers don't get to pick and choose what laws to enforce."
They don't?
Gee, then I hope they arrest themselves for their March Madness football pools (illegal gambling) and issue tickets to everyone's house or business they visit that has such a pool.
I also hope that they stop and issue tickets to every jaywalker they see, and stop everyone going 1 mph over the speed limit.
Peace officers have broad, broad discretion as to what to enforce and what to let go. If they didn't, and if they didn't use it, the laws would have been changed long ago.
Yes, they did.
I'm using the past tense because we don't have Peace Officers anymore. I miss them.
We now have "Law Enforcement Officers", and your observation about them neither having nor utilizing discretion is correct.