In what ways are these charities? I thought charity is about giving to people in need, not supporting political organisations.
Very few charities are not political organisations. I work in financial audit and our firm is something of a charity specialist. I cannot think of a single one which is not politically active. Try to think of a charity and then consider why and how they may be trying to influence government and the public - they're highly likely to be doing it.
To be clear, doing so is often an effective use of their resources in attempting to achieve their objectives. You may be thinking of your $10 donation being a few food parcels for some "save the kids in Africa" campaign, but it's going to take a lot more than that.
For what it's worth I wouldn't trust research findings from a charitable organisation either. Aside from obviously having an organisational bias, they likely got the money from a grant (or paid a researcher similarly) and the application will specify outcomes and milestones and you can be damn sure they don't involve "taking appropriate action based on scientific results". A charity's accounts, prospectus and websites etc (in UK anyway) specify the trustees and their occupation - I consider this disclosure the most important of all...
As part of the audit we have to consider if the charity is really doing the work of government and it's often a tricky question. Sometimes it's quite clear that if the charity wasn't doing it, the government (local or national) would have to do so, and they're usually providing a lot of the funding. I suspect a lot of what the government claims to do are things they pay a charity to do.