[Tithesmeister]

Maybe this will help.

All priests were Levites.
But all Levites were not necessarily priests.

All roses are flowers.
But all flowers are not necessarily roses.

Aaaand . . .
Premarital sex is fornication.
But all fornication is not necessarily premarital sex.

Homosexuality is fornication.
But all fornication is not necessarily homosexuality.

The same for bestiality.
Etc.