how about 100.000+ bots running the same routes and quests over and over again....
Even IF (and that's a big if) 100,000 bots all ran the same profile you'd have all of the below to factor in as well.
I know that everyone thinks that if a public profile is widely used, then it will be noticeable, but I am going to have to disagree. Like really... >12,000,000 subscribers in the US alone (As of 2008), and you think that our community alone is going to cause a specific path to be noticeable.
Especially after you think about the new nav system, there really isn't one SPECIFIC trail a bot will use while in "Quest Mode". Grindbot on the other hand, I could understand how there may be a similar path here and there in between bots, but even THAT is highly unlikely, simply due to they would have to be similar faction, botting the SAME location at the SAME time, be on the SAME realm... there are plenty of factors that make the chance of two bots in the same location highly improbable... and unreasonable to use as an excuse to not share or give back to the whole community.
You also don't factor in the consideration that if EVERYONE publicized ALL of their "private profiles" then there would be a large variety of profiles for a user to pick from, therefore "dispersing" the customer database, and not making one profile so noticeable.
I probably could continue going with more logical reasons as to why sharing profiles with each other is way better than having "private profiles", but I don't think any of you care, or even take a moment to consider what I've said.
tl;dr: You have no excuse not to share your profiles besides your own selfishness. So there.