Why should I care about the politics of the
software company I use
One obvious reason would be if the company in question is directly supporting various causes that you like or dislike.
You might also choose to care about the people working at that company. Suppose they support and/or practice policies that are harmful (or beneficial) to their employees. You might choose to discourage (or encourage) such policies by voting with your money.
Really, your question is disingenuous -- surely you understand? It seems like you simply don't want to care or don't feel that giving or witholding your support will make a sufficient difference. That's your call. Just be honest with yourself and others.
You might also choose to care about the people working at that company. Suppose they support and/or practice policies that are harmful (or beneficial) to their employees. You might choose to discourage (or encourage) such policies by voting with your money.
Really, your question is disingenuous -- surely you understand? It seems like you simply don't want to care or don't feel that giving or witholding your support will make a sufficient difference. That's your call. Just be honest with yourself and others.