All it says is "reasonable" break time which leaves it fairly open to interpretation by both employee and employer. It also doesn't say that an employer has to like it and not be resentful of nursing mothers.
Employer liking it or not has nothing to do with it, if the employer is subject to Fair Labor Standards Act (FLSA) they are required to abide by it (for any employers or managers reading this that frown on allowing break time for nursing mothers you should consult with your HR Department or Attorney. You could be subjecting your organization to potential liability).
Regarding "reasonable", this is a fact sheet and not the actual reg. If you are an HR pro or a lawyer then you should be looking to the reg and the official commentary to determine what "reasonable" is.
"This fact sheet provides general information on the break time requirement for nursing mothers in the Patient Protection and Affordable Care Act (“PPACA”, which took effect when the PPACA was signed into law on March 23, 2010 (P.L. 111-148). This law amended Section 7 of the Fair Labor Standards Act (FLSA). "