Some people find this confusing. Section 1201 of the DMCA has two parts. One part bans circumventing DRM, and the other part bans distributing devices that can circumvent DRM. The Section 1201 exemptions published by the Copyright Office only apply to the first part, not the second. I imagine it works this way because the companies lobbying for the DMCA to be passed didn't want to make it legal to sell or distribute circumvention devices as long as someone has a legal right to break the DRM, as that would defeat the purpose of the law.