Giving someone physical space doesn’t mean you’re a prude, it means you understand social consideration. You wouldn’t rest and arm on your buddy’s shoulder while you’re both at the urinal, so why would you crowd a cyclist while passing on a street (hopefully on a straight road with a safe break in traffic).

The Tasmanian Department of State Growth raised this question (or variations of it, if we’re being honest), and addressed the issue with a humorous short commercial. http://momentummag.com/distance-makes-difference/