It's because it's made of vinyl, duh! A material that's as slippery as a politician's promise and as prone to melting as a poorly made candle in a toaster.
Try using it as a makeshift sled for your cat. The look on its face will be priceless!
Or maybe it's just a sign from the universe that you need to upgrade to a tablecloth made of actual cloth.
Or maybe it's just because you're a rebel, a rule-breaker, a nonconformist... who also can't afford actual tablecloths?