In a way, yes. What is mature and professional behavior are decisions made by society. It's an opinion, but a consensus opinion of the society you participate in.
All manner of behavior - that you shouldn't steal, that you shouldn't lie, that you shouldn't wear your trucker hat to a business meeting - are all just the opinions of society. Some are made into legal contracts while the rest remain social contracts, but that doesn't mean they're any less important or valid.
All manner of behavior - that you shouldn't steal, that you shouldn't lie, that you shouldn't wear your trucker hat to a business meeting - are all just the opinions of society. Some are made into legal contracts while the rest remain social contracts, but that doesn't mean they're any less important or valid.