Can you tell me what is altcoins , please give me brief explanation about it and how we use it?
Simple: Any coin or chain that is not Bitcoin. That said, your question is off-topic.Hardforks with two surviving chains are not a type of voting mechanism. What you are describing is called a failure of consensus.
I have to agree with this, and this is one of the primary reasons for which such "implementations" shouldn't be promoted. AFAIK Bitcoin.com has BU as their "featured wallet", so they shouldn't be complaining that BTCT primarily has Core (hypocrisy?).PS - Maybe it is time to include Cyrus on that page. 
Good catch, time to ping theymos!