It's an incorrect understanding that assumes jobs are a zero sum game. But jobs can beget more jobs. For example, a company may wish to expand into AI. But maybe to do so competently it may need to hire at least 50 people. If it can't find enough people it might not make sense to expand into AI at all. By bringing in 25 workers, they would be creating 25 jobs for domestic workers.

Then there is the fact that immigrant workers create demand in other parts of the economy. They eat out, start businesses, buy cars, etc.

Finally, we shouldn't forget that these tech companies make massive profits. They can afford to pay all their employees very well. If domestic workers fear eroding wages, they should organize with immigrant workers instead of dividing themselves.