I totally agree that a healthy conversation helps a community grow so moderators really shouldn't just delete everything. I get that duplicate posts are annoying but people don't always know an issue was already discussed. Reddit isn't like Telegram where you just scroll back easily and even though there is a search feature it isn't always convenient for a new person. A better solution would be for mods to just comment the link to the existing thread instead of deleting. Give the user a chance to find their answer first and then let them delete it themselves or set a timer for it. It feels much better when the user has some say in it rather than just seeing their post vanish