A: The reason your company is in business is because your clients want to buy what your company makes. What your company makes are ideas and words and pictures and pieces of persuasion that your clients don't have the internal resources to produce for themselves. Without your creatives, you'd have nothing to sell.
So, as the manager of these creatives, your role is to make their job as productive and rewarding as possible. By that I don't mean you should meekly accede to every petulant demand they might make. I mean you should try to understand what it's like to be expected 'to be creative', and on a daily basis at that, with deadlines to meet and dozens of people invited to pass judgement on your fragile work.
I know that what they produce isn't high art - and nor should it be. But you can't crank out ideas of any kind to order without some degree of anguish and self-doubt. You may think all that a bit pretentious - but next time you hand your creatives a new brief, take it home with you yourself and see what you've made of it by Monday morning. You'll find it a salutary experiment.
What they wear is important. It's a bit like a football strip. It gives them security and identity. If you instruct them to smarten up, on the grounds that what they're wearing is 'not acceptable work attire', they'll know for certain that you simply don't get it. And you won't be doing what your company pays you to do.