Have I said something too harsh? He took this personal and report me to my eldest brother, my brother said I shouldn't mind, he doesn't know that my brother is now also a Bitcoin investor, my mistake was making it public, which my brother never did.
The tone of your answer is somehow disrespectful. You can just keep quiet and pretend to listen and do what you wanted to do. Instead you flared out and answer your uncle disrespectfully when your uncle just wanting to extend his concern to you. He has a point, Bitcoin may or may not fail one day, if you put all your resources in Bitcoin and it fail one day then you will be in trouble. Looking to add another source of income is always better than having just one.
From what OP said, it seems his uncle is quite patriarchal and always wants others to listen to him. The OP's behavior is a bit too harsh, but in that case, getting angry is inevitable. And in the end, they are our uncles, not our parents, they shouldn't go beyond their authority to tell us what to do and what not to do. While we are old enough to take full responsibility for our own decisions.
If you are still planning to get into Bitcoin, don't post anything about it in family group chat or on your WhatsApp status, this was my biggest mistake.
You hate your uncle for advising you what to do and yet you are here telling us what we need to do. You hate someone giving you advice and yet you are here giving others advice isn't it ironic?
I don't take that as advice, it's the imposition of their thoughts on us, and I won't be able to follow them. And I agree with OP's point, we should not brag about our investment in social media to avoid unnecessary trouble.