People make that assumption because facebook is filled with social people rather than anti-social people who worry that someone they 'like' might actually talk to them.
In normal social circles there an expectation that the you want to hear about things you 'like'. For instance if in real life I have a friend who 'likes' classical music then when I hear something about classical music I will talk to them about it.
Also like is not like subscribe because the idea behind subscribing is that you receive everything. For instance if I 'subscribed' to a magazine I would be rather upset if they only sent me every 7th issue, or only sent me issues when the newspaper had not arrived.
In normal social circles there an expectation that the you want to hear about things you 'like'. For instance if in real life I have a friend who 'likes' classical music then when I hear something about classical music I will talk to them about it.
Also like is not like subscribe because the idea behind subscribing is that you receive everything. For instance if I 'subscribed' to a magazine I would be rather upset if they only sent me every 7th issue, or only sent me issues when the newspaper had not arrived.