I honestly don't see that much hypocrisy on this point. People in tech who are supportive of expansive rights for foreigners to immigrate to the US generally ground their argumentation in either claims that it's immoral for the US to limit immigration (the view characterized by the slogan "no one is illegal on stolen land"), or claims that they benefit from immigration even if they are competing for jobs with immigrants. And often the people making these claims are socially adjacent to immigrants in their workplace or other social circles.

Meanwhile, the people in tech who oppose immigration often do bring up the same argument you do - that it's bad to allow immigrants to compete with blue collar American citizen labor even if this competition would make some things that these white-collar tech workers buy cheaper - or ground their opposition to immigration in negative effects of immigrants on American society that aren't directly related to competition for blue-collar jobs (generally, that the presence of large numbers of immigrants has bad cultural or political consequences for the US as a whole).

The political fight over immigration among white-collar tech workers I think has more to do with battling moral claims, or different visions of what the US should look like culturally and politically, than it does over purely-materialist job competition concerns that they are hypocrites about when the job competition is happening to blue-collar workers.