With the recent Community Guidelines change, there wasn't really a need for an actual "Polls" category, since many of the lower content poll type questions, like "X vs Y", or "what's your favorite..." and similar - that were just asking for random lists, or a straight yes/no answer were no longer allowed.
When a poll type question has an actual purpose to it, such as "Thinking of buying a new car - which one is better for commuting in traffic, a Honda Civic or a Chevy Cruise?" or "I'm having a party next weekend, what songs can I play that will keep the mood upbeat?" or "My son is 8, would an iPad or a Kindle Fire be more appropriate for him, and what are the pros and cons of each one?", then there are already other more relevant categories that the questions fit into, making the all-purpose one more or less obsolete.