California bill proposes to require political contribution data, but only from for profit corporations

It's important to remember that the controversial Citizens United decision struck down certain federal campaign finance restrictions on not just for profit corporations, but also unions and non-profits. Yet, while evisverating Citizens United has become a major goal of the political left, you rarely see the politics on display so obviously as in California Senator Noreen Evans's proposed bill that would (per Keith Bishop):

... require corporations to issue a report on planned political spending as well as expenditures for the previous fiscal year.  The report must include the following:

•  A description of the political activities.
• The name of the person, candidate, committee, or political party, or a description of the political cause, to which each contribution or expenditure was made.
•  The aggregate amount of the contribution or contributions and expenditure or expenditures for each candidate, ballot measure campaign, signature-gathering effort on behalf of a ballot measure, political party, or political action committee.
• If a contribution or expenditure was made in support of or in opposition to a candidate, the office sought by the candidate and the political party affiliation of the candidate.
•  If a contribution or expenditure was made for or against a ballot measure, a description of the ballot measure and a statement as to whether the contribution or expenditure was made in support of or in opposition to the ballot measure.

Predictably, the Democratic Senator's bill fails to impose any comparable requirement on unions or non-profits. Hmmm. I wonder why?