What the bill stripping Broadband Privacy rules does is make it nearly impossible for the law to set a precedent for what should be considered illegal to sell when it comes to users' data. What may have happened if broadband privacy rules were enacted as intended here[https://www.nytimes.com/2016/10/28/technology/fcc-tightens-p...]
... someday somebody who didn't "opt out" would have discovered their [medical, financial, insert whatever] data had been sold to their detriment. Lawsuit. Legal scrutiny. Precedent == Baseline for what is acceptable and what is not for people who don't opt out.
Now, with no consumer privacy rights by default on broadband, and no neutral delivery system (net neutrality), and with provisions the GOP inserted into the Broadband Privacy rollback explicitly to make it harder to sue entities who sell your data, the default situation is already stacked badly against the average person.