When we judge people's taste, we often end up judging the people themselves.
Something being tacky means the person behind the clothing is also tacky. Their tackiness becomes a feature by which they are judged. And they are made lesser for it.
The implication is that the judger is not tacky at all. They are above the tackiness, and so have some quality that makes them better.
Which is nonsensical because many (mundane) things have no link to the moral character of the people behind them. A gaudy piece of clothing might not be something you will ever wear, but what does it have to do with the person who does wear it?
Your judgement, based on your own taste, is not also a moral judgement on the character of people.
What's more likely, is that the judgement segregates you from others. It places those that are judged as lacking. Using 'taste' as a proxy, people are looked down upon through some conveniently declared failing.
It means that you are not really expressing an opinion on taste. Instead, you are indirectly attacking people.
So judge the thing, not the person. In most cases, this is appropriate. Express your own taste and opinions as much as you want. But distinguish your treatment of the thing from actual people.