Wait, non-profits (generally seen as organizations doing good by their very definition) cannot lobby but other organizations (with making money as their principal goal) can?
> This isn't true at all. They just don't pass profits to shareholders.
"The exempt purposes set forth in section 501(c)(3) are charitable, religious, educational, scientific, literary, testing for public safety, fostering national or international amateur sports competition, and preventing cruelty to children or animals. The term charitable is used in its generally accepted legal sense and includes relief of the poor, the distressed, or the underprivileged; advancement of religion; advancement of education or science; erecting or maintaining public buildings, monuments, or works; lessening the burdens of government; lessening neighborhood tensions; eliminating prejudice and discrimination; defending human and civil rights secured by law; and combating community deterioration and juvenile delinquency."
A charitable nonprofit allows its donors to take a tax deduction. If you run a non charitable nonprofit (donors don't get a tax deduction, but the corporation is tax exempt) or a corporation that happens to not make any money (pays no taxes de facto) then you can lobby.
> Wait, non-profits (generally seen as organizations doing good by their very definition) cannot lobby but other organizations (with making money as their principal goal) can?
Non-profits (including some tax exempt non-profits) may lobby, but charities are more restricted [0]. Note that charities -- 501(c)(3) organizations -- are not just tax exempt, but donations to them are tax deductible to the donors, which amounts to a public subsidy of donations that increases (due to progressive marginal income tax rates) with the income of the donor.
[0] But they may still lobby...as noted in the IRS page referenced upthread, charities "may engage in some lobbying", but lobbying can't be a "substantial part of its activities".