I agree it doesn't benefit the Teamsters. But the Teamsters DO endorse illegal immigration.
WHEREAS, the United States is a nation of immigrants founded on the shared ideals and rights of democracy, freedom of speech, religious tolerance and equal oppo
teamster.org
It's right there on their main page. They want to legalize tens of millions of competitors for labor, and bring in more.
When any labor comes in, it pushes labor markets around so that the supply is increased in Teamster jobs whether or not the illegals themselves take the jobs.