> Sounds to me like voting with your pocket book.
It's very interesting that you would compare it to voting, because that means we're talking about citizens of one country "voting" for the leader of another country--which would mean interfering with another country's elections. Are you sure you want to stick with that analogy? :)
This is in contrast with the traditional definition of "voting with your wallet," which refers to refusing to do business with companies you don't like.
> How is this a bad thing?
In a nutshell, it's bad because it further contributes to polarization and division. This becomes a self-reinforcing cycle, leading to ever more "us vs. them" thinking. Eventually it's what leads to wars. Isn't it fairly basic political theory that nations which are economically interdependent are less likely to go to war with each other? If we can't do business with anyone who has different political opinions than we do, that's a recipe for...well, war.
> Would you also object if I didn't want to purchase clothes that are manufactured in a way I find morally deplorable? Hey it's not the workers fault right?
You're comparing apples to oranges. This is not a question of a company mistreating its workers.
By the same token, I could ask you why you would punish the innocent workers who didn't vote for the candidate you dislike. By refusing to do business with them, you are hurting them, and it's not their fault the candidate got elected. Even from a purely pragmatic standpoint, this is likely to drive them away, toward your political opponents, who can tell them, "See how nasty the other side is? They won't even trade with us anymore because they disagree with how we run our own country!"
That attitude is essentially a large part of why Trump got elected: the Democrats' constant condescension toward a large swath of the population alienated them. If you mistreat people, they aren't going to thank you for it, they're going to hate you for it.
Or, colloquially, you can catch more flies with honey than with vinegar.