I can understand if this is considered weird, but honestly, I think the things that are sensitive or not worksafe are marked as such. The three pictures you mentioned are probably some of the least offensive in my gallery.
I don't mean to sound rude, but I'm really not asking for an argument. ~.~ The crosses--the symbol of Christ's shedding for our forgiveness--, and the content of this image being of sexual themes really makes this easily deserving of being marked mature. The other images follow in how scant the clothing is on the subjects and the detail you draw beneath the clothing.