could somebody explain to me the basic idea behind fatwas like are all fatwas was supposed to be accepted no matter?

Why do people give fatwas that go against the commands of allah and his messenger, because then some people believe because a scholar said you can do it, it is okay, even though it is against the commands of Allah and his messenger.

it just seems like they're often time excuses to go against what we should be doing but then why do people do them for example some people give fatwas that it is OK to purchase a house in the west with interest even though interest is clearly haram so some people will follow that fatwa and some people are like no you can't follow because it's clear so then how are we supposed to know which want to do?

And when is it OK to follow fatwas?

Also is there blame on the people if they follow fatwas even though they are haram?