So if I'm Catholic, it's OK for me to drink almond-flavored dairy-milk during Lent? Win!

From medieval and Renaissance-era recipes, religious rules appears to be the main reason almond milk is used. Because it's not dairy.

Not sure about that, but I do know that if you want to eat capybara on Fridays as your fish dish you should be fine.

Do you have a problem with the name "peanut butter"? It isn't butter with peanuts in it. Or mincemeat pie, which isn't made out of minced meat?

Proper mincemeat pies contain suet and have a very different taste from the vegetarian ones. So yes, in that case it is a problematic name that conflates two usefully distinct things.