Why do guys ditch their platonic female friends without explanation?

If the guy doesn't have a girlfriend and/or is not gay, then what is the reason? Otherwise, to do that is presumptious of them and extremely rude. No wonder women think men are a**holes. It happened to me. One of my best friends (who happened to be a man) stopped communicating cold-turkey and despite my best efforts at renewing the friendship - I did nothing wrong - it didn't work. At least my former female friends gave a reason why they severed communication.