I have the same issue when I'm on a desktop application (web player or actual program) , however, the "Report Explicit Content" option is full available in the mobile app. FYI, I have a Samsung Note 8, but I'm sure the same would apply on the Iphone.
It is an excellent tool! I built a playlist for my 5 year old when we do our weekend dancing and shenanigans lol. The explicit oe E tag helps me quickly identify what I can and should not add. Also, in many cases, a song will have a regular version and a "radio edit" or "clean version.