Why do people share excerpts of their script for feedback?

Just a quick rant.

So often, people online will share tiny portions of their script - single scenes, whatever - to get targeted feedback, as though that little chunk of story exists in a void. I don't often give feedback to random scripts on reddit, but it's really frustrating when I want to, but the bit they give me isn't enough to give them the advice they want.

Sometimes I want to be able to skim what came before to see if an issue is repeating in their work, or if it's just showing up here. Sometimes it depends on information that they think is obvious because they came up with everything, but is actually completely baffling without some earlier bit of context. Sometimes it's what comes next that's important, as we need to see how a given event plays out over the course of things.

I get that it often comes out of a place of wanting to be polite and not waste time - "I don't want them to think I expect feedback on the whole script, so I'll only share the relevant parts" - and I appreciate that, I really do. But just give me the whole script anyway, and tell me you're only asking me to read pages X through Y. I promise that even if I do read more, I won't hold it against you.