Currently all the new ICO are trying to develop platforms with different use case than Bitcoin, not similar at all, why people keep calling them altcoins although they are not alternative?
They are just an alternative so we are calling it altcoins and that makes sense. Bitcoin is the original coin so if someone says or talks about bitcoin, we are mainly calling it as simple as 'bitcoin'. But when it comes to other coins that are less popular or if it is popular and has a good market cap still we are preferring it to call as an altcoin because they are an alternative to the original.