I can never understand why people feel the need to list what they own in the first place.
I suspect the reasons vary from one person to another. Sometimes I find it quite helpful to see what lenses people own when they are giving advice or commenting on their experience. If they say lens XYZ is absolutely the best you can see what they may be comparing it to. Of course you can't know what they may have borrowed, rented, or owned in the past, but it is better than no information at all.
Ok, I'm up to 3 posts, only 7 to go before I can add my (modest) list of gear!