Why do some religious Jews eat pork and shrimp?

[DocCathode]

@Excalibre

So how about it, DocCathode. Do all Jews who keep kosher do so to the extent of trying to avoid the barest possibility of “contamination” with treyf foodstuffs?

No. That would mean- not eating at restaurants which are not certified glatt kosher, never eating any food (regardless of ingredients) prepared in a kitchen which was not glatt kosher

Can a Jew who keeps kosher eat at a non-kosher restaurant - or rather, is it common for Jews who keep kosher to do so, even if most Rabbinical authorities would say that such food is automatically treyf?

Whether a Jew eats at a nonkosher reaturant is up to them. Many Jews who keep kosher do.