I had to learn how to be that guy. The gym right by my house has a large outdoor pool open only 3 months and only allow a single lap lane. Several people like to think that the lane line is solely there to protect them from other pool users. Most people choose to just swim indoors instead of deal with it. I'll swim around them, but a couple guys will purposely slide over and stand as spread-eagled as possible. I'm not being forced indoors on a beautiful day because 1-2 people insist the single lap lane in a huuuge pool is for standing in. They get the depth charge flip turn. You would never purposely block or stick your leg out at somebody on a bike path, the pool shouldn't be any different. There's literally 95% of the outdoor pool left to hang out in.

If somebody is in the lane and moving, I always make it a point to stop and talk to them, ask if they want to borrow goggles or be my pen pal. Swimmers got to stick together when you're at a huge gym that can't figure out lap swim times and explicitly bans lap swimming on the weekends. The weirdos that purposely sit in the lane designated for lap swimming deserve to be reminded that it's for people trying to exercise and the other 95% is for peeing and skeezing on underage girls.

Hmm, I ranted a little harder than expected. I usually just check this thread to see if I'm the strange denizen.