Please take a moment to get my point before you conclude. I know a lot of people judge a post by the topic alone and if that is applied to mine, I might be sounding anti-bitcoin since selling is highly demonized by a lot of people in this community.
Well, some who advise holding Bitcoin are just concerned about the possible future profit, at least they wanted to remind newbies that holding Bitcoin for long term can possibly bag him huge profit and I think it is not bad, but selling is not highly demonized by major member of the community, as a matter of fact people who are holding Bitcoin had been trading them for good and other stuff, if you only look at the goods and collectibles section of this forum.
Now the question is, assuming everyone who ever bough bitcoin is holding their bitcoin in their private wallets, what will be the fate of bitcoin and the bitcoin network? Does holding bitcoin strengthen the bitcoin network?
It is the miners that strengthen the network not the holders of Bitcoins.
If no, are those who sell and more their bitcoin on-chain generally doing bitcoin bad?
Not doing bad, actually, it is a good sign because if someone sells and someone buys, the coins possibly pass to new hands. Holding and trading are part of the Bitcoin economy so I do not see anything wrong if someone sell their BTC.
I believe that Bitcoin will be much more beautiful if a good number of human populations are using bitcoin for their daily lives and have real testimony that bitcoin actually made their lives better. We cannot achieve that if we only encourage people to buy and hold, can we?
It is really great if Bitcoin is used as a payment option, this gives way for bitcoin holder to have more options to spend their BTC.