Saying restrictions don't matter - because it's bad etiquette and shouldn't be done anyway - is exactly why people react to the restrictions.
"Well, people shouldn't be eating at their seats anyway...."
"... people shouldn't be flying so much anyway...."
Etc. etc.
NO. Want to change the rule? Change the rule. Don't use the p@ndemic to push your own agenda, whether it's etiquette

, the environment, or anything else. Or tell people who are being restricted that it doesn't matter they're being restricted because they shouldn't be doing it anyway, when it's perfectly legal/customary.