haven't people heard of genericized naming? The first "real" tablet on the market to gain any market share was the iPad. The iPad has since become associated with every tablet device, with the possible exception of the kindle fire, because people associate that as an ebook reader first. I imagine a lot of people are lazy and don't want to say computer tablet or whatever (and just saying tablet can be confused with a tablet of paper), and just say ipad. They are not using it to mean an apple device, but a tablet computer. It's the same reason people often refer to non-apple mp3 players as an ipod. it's often easier than saying "it's an mp3 player... similar to an ipod, but made by XYZ and cheaper". When a company dominates the market as much as apple does, it is expected that people will start to genericize the product's name. It's not a matter of competitors intentionally fooling the masses, but rather that the masses haven't really seen the other devices.
With android, the same is also true. The term iphone is so well known now that many people use it to refer to all smart phones. Saying please, no using your iphones during XYZ is often easier than saying smartphones or whatever, and everyone knows what the speaker means. When one company spends billions advertising their device, it's no wonder other people ask for another companies version of the ipad. The samsung galaxy tablet performs many of the same functions as an ipad, so to many consumers, it is samsung's ipad. They realize it's not the exact same thing, but if it can perform the same functions, than why not refer to them the same way. With apple performing so much marketing, and having the mindshare they have, it's no wonder other companies have a hard time distinguishing their products from apple's.