It's called following distance. The wisest among us try to maintain it. You probably *are* cutting them off to an extent, as far as eating up the cushion they're trying to maintain, but you gotta do what you gotta do.
There's one spot on my regular route where I have to come off a clover leaf and then make it across four lanes of traffic to the extreme left within about 1/4 mile. That gets interesting sometimes.
Actually, there are *two* such places I can think of.
Tell me about it. Milepost 279 on I-40. Why the hell can't those idiots figure out that the right two lanes exit off, and the left two lanes go through? WHY???
Been there, done that. Hooo boy, have I ever. Try passing on a two-lane road in a non-flat part of the country in a tractor-trailer too. It can be done, but it's extremely difficult to find a spot with enough sight distance to do so safely, and finding such spots at a moment when there is no on-coming traffic is damn near impossible.
(And when you finally get around Grandpa after 50 miles of torment, you look in the mirror to see if you're clear, and see that he's in the process of turning off.)
I could spend a couple of hours scaring the hell out of you with blind spot stories, but for the sake of argument, we'll just assume that particular driver was a total maniac and let it go.