Your employers are interested in their interest. If you're going to be using your money in an interest category where your win is their loss, they were care proportionally to your effectiveness, no matter the methods.
Now :
>How could they not be? The ability to advocate for yourself has been given to someone else, over something as intimately personal and important as the labour you undertake for the majority of your waking hours.
You can structure a union in such a way that hierarchy is very weak and involvement is direct. The reasons why this often isn't the case are interesting, and you should read about them.
The root if the issue is this : your ability to advocate for yourself is almost nil. You need to get together with your fellow workers to have any impact. By doing so, you will lose some of the flexibility in your advocacy, but will receive greatly increased power.
Literally the only politically effective lobbying group for the average person is a union. There have been many studies done about it.
I have second hand experience with four unions, and first hand experience with two. All but one were great, and the one that wasn't was clearly deficient for obvious structural and social reasons thah could be addressed.
In any case, you're free to continue wasting your money. You will be contributing to PACs that will eventually get bureucratized, ossified, ostracized, and turned against you, and because you plan on aligning yourself with extremely narrow organizations that lack the power to withold labour, they will collapse and crash.
Not only that, but success in such politics is a question of money and connections. The entire tech sector, totalling tens of trillions of dollars in valuation, is better connected than you are, will be able to vastly outspend you, and will do so in a much more efficient way than you can via a heterogenous network of PACs.