@Pandya Not sure why Acharyas are saying so. Probably they are not speaking in the strict sense but only loosely using that term Smriti. In the strict sense one should differentiate between the scriptures as shown in the scriptures.
@Pandya Where did Vyasa write that? In Brahmasutras? Then Vyasa in Vyasa Smriti says that Smritis have more authority than Puranas. Same he also says in Puranas which are also his works.
In general the statement "All scriptures which are not Sruti are Smriti" can not be proven from scriptures. Also Manu Smriti clearly defines what a Smriti is. @Pandya
Btw, I don't consider "all scriptures which are not shruti is smriti" after I posted this question in which I broadly categorised the scriptures :) @Rickross
