If a group could be considered a "tea party" group, that pretty much indicates that it's primarily a political group; the term "party" specifically refers to a political institution. If a tea party group does some form of social welfare, that doesn't change the fact that it's primarily a political institution.
Planned Parenthood, on the other hand, is unquestionably a social welfare organization. It has offices which have doctors who provide a wide range of sexual and reproductive medical services to many women who would otherwise be unable to obtain them. If you look at their budge, 70% goes directly towards medical services. Less than 10% goes towards public policy; and what does, is advocating for policies to be able to continue the social welfare services that they provide, nothing else. Those figures you linked to for donations to political candidates represent less than 0.05% of their budget.
Where are the tea party offices that provide medical services to low income residents? Or heck, if you want to be fair to them, where are the tea party offices that provide tax advice to people who want to lower their tax burden? Of course, it's kind of hard to come up with examples of social welfare services that tea party groups could provide, because as far as I can tell, the tea party movement is primarily about opposition to social welfare, and a variety of political goals involving the reduction of the federal government. Even trying to stretch my imagination, I can't think of any social welfare programs that tea party groups would actually provide. I suppose they could qualify for tax exempt status if they shipped 51% of their revenues to other social welfare organizations that they supported, but that seems more like a tax dodge than an honest assessment of the purpose of the organizations.
Now, back on topic, I think that the software groups are sometimes more of a grey area. While there is a lot of open source software that is developed solely for social welfare reasons, there's also a good deal that is developed primarily by for-profit corporations. If there will be more than one for-profit company working on a joint project, it is common to set up a non-profit foundation that organizes the collaboration, or use an existing one. On the one hand, this can sound an awful lot like for profit companies trying to claim that their joint venture is actually a social welfare organization. On the other hand, due to the fact that the code is shared publicly and available for anyone to study and modify, it is arguably promoting social welfare and thus should be eligible.
If you check the actual recommendation, you will see that they have no specific recommendation for this type of situation; all it advises is "The [sic] is no specific guidance at this point. If you see a case, elevate it to your manager."