I think it is one thing to see someone attempting to belay/lead or whatever and offer help if they are screwing it up and perhaps endangering themself or a partner. It is altogether another thing for someone to solo or even boulder and that is simply a choice that does not require anyone else's comment or approval. Let them get in the zone and don't distract, please. I also believe this is an endevour that is most rewarding away from the crowds but that is only my take. Clearly, not everyone feels that way and nor should they have to agree.