It’s a combination of a few things:

(1) Tech demands a lot from its employees. We are dedicating a significant portion of our waking hours. They expect us to believe in their mission, and so we also expect that mission to align with our values.

(2) Technology itself is much more far reaching than any other industry. These corporations are massive, and with them massive budgets for lobbying etc. Not demanding that they reflect the values of their employees and customers would be a massive waste of that power or worse — letting them actively use that power to make the world worse.