I completely agree that the dress code is all about control, but as far as gripes against the WTS are concerned, this one is about number 10,001 on my list. There are at least ten thousand better things to go after these guys for
It's a big picture thing. I get that it can seem petty to criticise a requirement to dress like a salesman from the 50s, but it's about more than just that. They use the requirement, and the average JWs acquiescence to it, as a stepping stone to ensure that JWs follow other requirements. More insidious requirements. Requirements like shunning their children or dying for want of a blood transfusion.
Research shows that if you can get someone to do you a small favor, they're more likely to do you a big favor later than if you jumped to the big favor straight away. It's a significant part of human psychology that all cults take advantage of. It's about more than the clothes, it's about what they use the dress requirements to accomplish, and I suspect that most of those 10,000 grievances of yours are in some way related to their control, and a big part of their control is rooted in getting people to make small sacrifices early that eventually escalate into bigger and bigger sacrifices.