My understanding of that verse is that the fool denies the existence of the Lord in his heart because he does not understand how God can both be Omnipotent and loving in light of the evil that we see in the world.
So, it is not that only the fool is the subject of total depravity...for scripture teaches that all are in the state of depravity from conception...the fool denies the existence of God because of the reality of total depravity...for he does not understand how God can exist in light of the fact of it.
So yes, Mary is indeed included in the "all" of Romans 3:23. Jesus Himself is the only One who is not included in that mess...2 Corinthians 5:21, Hebrews 4:15, 1 Peter 2:22, 1 John 3:5. No verses in scripture like that about Mary...unless you want to change the spelling in 1 Corinthians 7:28, reading it phonetically...

. Maybe that's where they
get that doctrine, for all I know...