what exactly is spam?

It means unwanted messages. Someone created an acronym after the fact: Stupid, Pointless, Annoying Message.

Spam is a condensed word for the product which is 'Spiced Ham', yes its made of pork.

From Wikipedia:
Spam's basic ingredients are pork with ham added, salt, water, modified potato starch (as a binder), sugar, and sodium nitrite (as a preservative).
Hormel claims that the meaning of the name "is known by only a small circle of former Hormel Foods executives", but popular beliefs are that the name is an abbreviation of "spiced ham".

https://en.wikipedia.org/wiki/Spam_%28food%29

This has what exactly to do with religion or spirituality?

Spam's basic ingredients are pork with ham added, salt, water, modified potato starch (as a binder), sugar, and sodium nitrite (as a preservative). Natural gelatin is formed during cooking in its tins on the production line.

Yes, it’s pork. I heard spam stands for either shoulder pork and ham or spiced ham. 

if you can type, you can read the can.

WW2 it was mystery meat in a can with lots of fat and SALT. and filler such as potato starch and cornmeal flour all mixed together and colored just right in a can. Tons of it was made...which was better than eating NOTHING. SPAM still continues to be sold today in stores (though it is not the lower military grade foodstuffs) Consumers will not buy JUNK. So they had to up their game as canned DOG-FOOD WAS better stuff than SPAM.

Though today, when we talk about SPAM, it is more to do with excessive advertising on the internet and in EMail.  Tons of letters from the same sender selling the same thing(even though you blocked them they are still getting through)

It is when someone keeps sending you ads and then you want to eat some spam

its processed meat i think. I fell on a spam can and have a big scar across my knee and ankle