It can be argued the high majority of 'the herd' have, at some point, thought for themselves, as individuals, from different locations, and decided they want to go to x place to pay their respects. When they get there, x 100s/1000s are also there, having reached the same decision. Call it herd mentality if you like, however it doesn't mean there wasn't individual thought at some point in the process.
I would suggest the majority are doing it, because lots of others are doing the same - they see it as 'the proper thing to do', rather than their own decision.