Thanks to everybody for the answers, even to the nice guys that bumped my post.
I did some research on the subject, and it seems that some deodorants have a wax like substance that traps the odor and accumulates it in the fabric. I guess a human generated organic smell wouldn't be strong enough to resist alone several washes with commercial soap.
Now it's our duty to find a way to dissolve those deposits.
Do you wash in
Hot water?...If not do so.
Do you have a water softner?...If not use washing soda or Borax washing additives,...these will "scavenge" the minerals in the water that form curd.
Do you use an extra rinse?...If not, do so,...turn the washer timer around to rinse cycle after it is through the first time,...an extra rinse gets rid of detergent residue.
Do not use fabric softner, these intentionally leave a residue.