If the Democrats are "pro-immigration", they haven't actually succesfully done much to show it. Generally, not limited to H1B. this country has become very anti-immigration generally, and I hate it.

There isn't really such a thing as a "tech union" in the USA. I don't think very many tech H1B holders are working in areas with any unions. (And if they were wouldn't many union members be H1B holders themselves?)

Actually, I suspect Democrats get more money from tech companies that benefit from H1B hires than Republicans do. Tech companies in the past tend to donate to Dem more than Republican. Of course, the biggest companies, in nearly every industry, donate to both parties hoping to influence whoever is in office.

Perhaps that's what led to the bare improvement to a 60 day period under Obama, who was of course the last Democratic president. The Dems definitely haven't done any more for lower wage or less skilled immigrants, if you think they are somehow helping them but not H1B-type immigration, you are unfortunately mistaken.