No, it's not odd because of that. It also won't show up by default. You will literally have to go through the effort of going online to your Disney+ account and changing the rating cap as the default is TV-14.
Daredevil was only the third live-action Marvel show done by Disney/ABC Studios (via Netflix) only after Agents of SHIELD and Agent Carter. Then the subsequent shows, etc. It was thought that the characters were too dark for the MCU at the time, yes, but now we are two phases later and Feige has found a way to bring them in, in part because fans loved the characters (except for Iron Fist).
When Disney made the deal for Marvel to make these shows it was in 2014 as a part of an 8 year deal to license out Disney films and shows to Netflix. Disney+ wasn't even a thought at this point and time. Deadpool 1 & 2 along with Logan (along with these Netflix Marvel shows) showed Disney that their audience will show up for R-rated Marvel content. MODOK and Hit-Monkey have also been entertaining adult-animation shows on Hulu in the past few years.
My question is, they're allowing TV-MA/R content, when will we get Deadpool or Logan? Separate from Marvel, what about movies like Die Hard or any number of the R-rated Fox/Searchlight/Touchstone movies?