I think because BP is most effective when done as a separate step and left on the skin to do its work. The cleanser step is intended to prep your skin for the acne medication by washing away dirt and oils that would interfere with the medication's absorption. Medicated acne cleansers are typically not as effective because you cannot control other substances from entering the pores at the same time or ahead of the medication, which also interfere with the medication's absorption. By cleaning the skin first, you are ensuring the best possible absorption and maximum benefits from the medication, which is needed to treat very stubborn acne, and for some people even this is not enough.

Those with very mild nonstubborn acne can often get away with OTC treatments and medicated cleansers. Although most of the active ingredients in medicated cleansers go down the drain, enough are absorbed to be effective for some people. My son used Stridex pads for 2 years and they worked beautifully to treat his mild acne. As his condition progressively got more stubborn, we switched to medicated cleanser and BP for spot treatment, and now we are treating the majority of his face with BP and a nonmedicated cleanser.

Sounds like inflamed acne may not be an issue for you if you are looking to take things to the next level with exfoliants, etc. Glycolic acid is supposed to be a good exfoliant for helping red marks fade, and from what I hear, very hydrating, too! If you're looking for a medicated cleanser to experiment with, I highly recommend Neutrogena Oil-Free Cream Cleanser...2% salicylic acid, correct pH, noncomedogenic. We don't use anymore to treat my son's skin but I am using it maybe once a week for whiteheads. I found it too irritating for my skin for daily use but you seem like you aren't bothered by irritation from other posts of yours I've read.

Hope something in here is helpful!