In theory, for-profit should not necessarily mean bad (after all, many for-profit businesses offer useful products and services without being shady or scammy). However, in practice, for-profit colleges have produced a large percentage of the bad actors in terms of shady or scammy marketing and low quality programs that fail to help graduates find employment that will help them pay off their student loans.
Although a few programs at non-profit colleges failed the gainful employment rule (which DeVos wants to eliminate), 98% of the programs that failed the gainful employment rule were at for-profit colleges.
https://www.chronicle.com/blogs/ticker/over-800-programs-fail-education-dept-s-gainful-employment-rule/116378
https://www.chronicle.com/article/Here-Are-the-Programs-That/238851
Elimination of the gainful employment rule eliminates the questions that are being asked of the colleges that may be offering programs of dubious value to students who may use federal financial aid.