Old guy: well if I buy a ford and I don’t like it I can buy a Chevy
Zuck just doesn’t know what to say because the question is so dumb
Actually the old guys does have a point.
In the previous millennium people worked to develop protocols. With a few apps on tops. Email, messaging, file transfer, terminal emulation. Most of those protocols were proprietary. IBM's SNA, Decnet phase-4, Appletalk, Novell's Netware, Banyan Vines, etc. You could chose between them. But they wouldn't cooperate. AppleTalk machines would never talk Novell machines, etc. Closed technology. Some company was in charge of a specific protocol, a specific technology.
Then IP won. The TCP/IP protocol suite, as it called. Nobody is in charge of IP, nobody owns IP. Protocols on top of IP, like email (SMTP, RFC822, POP, iMAP), FTP, or later HTTP made it so that different machines made by different vendors, with different OSes, could talk to each other. Openness was a goal. Openness helped.
Then fuckers came. Like Facebook. Like Twitter, like Whatsapp, etc. Building techology on top of open protocols (IP, HTTP). But in fact those protocols and applications are closed. Someone is in charge. Someone is the boss. Someone owns that technology. The exact opposite of what the Internet is about. No open communication.
That old man's question is very valid.
What do you do if you want a particular service, but don't want to use Facebook ?
Google's facebook ? Nobody is on it. Hyves ? What ?
I don't do Facebook.
But I do Whatsapp. I was forced to by my collegues. I didn't want Whatsapp on my phone. I rather had Telegram or something else. Preferably something that uses an open protocol. But I couldn't. Because I would have been alone on Telegram. There is no choice. You use Whatsapp, or you use nothing. At least in my country. I bet it's the same in the US.
It's a very valid question.
Facebook is a monopolist. What is the alternative ? The real answer is: none.