I would even go as far to say, it might be a case of them believing that they are taking short-term losses to come out ahead of this in the long-term. Whether it will turn out this way in reality, we will see, but that line of thinking actually does make sense.
There's even a term for this in economics, called Animosity, which leads to economic imbalance: https://en.wikipedia.org/wiki/Economic_discrimination#Animos...
A country exists with a racial divide, let's say blue/green.
A blue person abuses a green person.
The green person does not fight back, and takes the abuse, knowing they are powerless in the society.
A different blue person, blue person #2, attacks the original blue person. This puts bp#2 at legal and physical risk, even though they were never under any threat of subjugation or abuse from the original attacker.
Blue person #2 would be said to have acted in a form of reciprocal altruism for the green person. This type of behavior is often seen, even in situations where BP#2 has little or nothing to personally gain, was never at any risk, and could potentially receive large negative consequences personally for their actions.
Clearly blue person #2 was also acting in a manner of animosity, that (more generalized) could or not be considered discrimination, economic or otherwise.
Many of the individuals supporting the trade war and tariffs know that it's causing them problems, but as far as they're concerned it's worth it to stop China from "screwing them over" or "taking advantage of them". This is not, in fact, an unusual thing- people are are frequently willing to take some personal pain to punish what they believe is wrongdoing or failure to adhere to social norms.
I happen to be on the side that believes the tariffs and trade war are doing more harm than good, but labeling those who disagree as stupid is exactly the sort of thing that leads to resentment, failure to communicate, and polarization, none of which are valuable.