Android is not the reason they won't message you, The lack of iMessage is. Nobody I know cares what kind of phone you have. But they do care if you have iMessage or not.
Lack of iMessage essentially breaks group chats. So if you don't have iMessage, and everyone else does, you will intentionally not be added to the chat.
Lack of iMessage also means sending videos to you is going to take additional steps compared to other iMessage users. So they likely just won't send you the video.
Over time, the additional steps required to include a non-iMessage user, means you will receive less messages from your friends.
I don't like the situation, but that's how it is. If the majority of your friends/contacts use iMessage but you don't, then you will be excluded from chats. Not because you use Android, but because it is just more difficult to include you without iMessage.