There really is no need to seek offence where none is given. It cheapens any further discussion.
Since you ask, I'm in a bike club because I like to ride, race and tour bikes with friends in my spare time. I've just finished a bike tour where about half the group where women. They also collect bikes just like me. Just like my friend, not all their partners ride or have any interest in cycling either.
I have 6 bikes because: a) I've been riding a very long time and I tend not to throw things away. b) different bikes serve very different purposes.
i.e. I don't commute on my TT bike and I don't ride my Brompton folding bike on single track.
As for sustainability, I suggest you look at the actual impact of owning a few old bikes vs say, having even one pet dog, cat or child. These are several orders of magnitude worse.
I own 6 bikes right now and want another. My best friend used to keep one bike in the boot of his car so his wife wouldn’t see it[1]. He’d then switch it with another every winter and spring[2].
We both own cars and drive most days, so these two things don’t seem that related. I would like to cycle commute more.
1. What really makes me laugh about this is, he chose the same paint scheme because that’s the only thing she notices; 1 is a winter road bike and the other a TT bike.
2. Until it all came out in the pub; she thought it was funny too. :D