Honestly, I am more sad that there are people who take something as insignificant in halacha as a black suit, white shirt and black hat and make them out to be the ikkur. There is NO inyan to wear those clothing, especially in the hot sun. So yes, I think wearing a suit and black hat to the zoo is ridiculous. I would also think the same about someone wearing a ball gown at the zoo or even a bathing suit. That is not someone who is standing up for ratzon Hashem – that is someone who is following an unecessary uniform in a place that doesnt warrant it.
If someone is making a FASHION statement, I look at it as such. Its a shame people don’t put more stock on the inside, rather than what is on the outside.