On a TA last November, there were several men in overalls. They also sported long beards. They came to dinner in Waves that way. When asked the staff, we were told they are from Northern Germany. Not sure what that has to do with it. Im sure in Northern Germany they are aware of what to wear to dinner.
To highlight another group, a large family with kids, were very casually dressed all the time, ill fitting sweats with too much flesh exposed. Their loud demeaner, matched their clothing choices.
I am all for wear what you want, but within reason as it does affect the ships atmosphere. On the other hand it gives you something to laugh at, albeit quietly.