Is that the real question? I don't really think so, but even if it were it's one with numerous obvious answers.
Some obvious answers:
Companies are made of people, so decisions that are made are often a reflection of the values of those people, not necessarily those of some country or another.
That some group of companies tends to be American is unsurprising since (a) America owns tons of 'loud' industries like tech, so it will always seem this way, and (b) unsurprisingly the values of those who make up a company are tied to some extent by their background.
Companies may feel that their targeted consumer groups are likely sympathetic with some specific social norm.
Companies may feel that the issue is in fact bad for business ie: that someone is a bad fit for a role, is incompetent, etc.
etc
It's so obvious I wonder why one would even ask.