There are badware programs that will attack anti-virus and anti-spyware products.  A proprietary compile makes it almost impossible for badware to attack a specific product.

Using the standard “same program for everyone” type of product is a weak link and makes it very easy for badware to find one common attack approach (vector) to compromise any security product across all computers in all companies and homes. 

Anti-virus and anti-spyware products only work if they are running.  If they are compromised by an attack, they become useless, or worse, if hijacked offer no protection only the illusion that the security program is still working.  The average user does not know they are unprotected.

Repelit custom compiles its program (executable) for each company.  Badware does not have a common way to attack Repelit; badware cannot find the Repelit process since it is company specific.  Add to that the fact that Repelit protects itself from attacks.  That is a level of protection and a level of custom service unique to itSoftware security products.

Proprietary compilation helps ensure Repelit remains running.  When Repelit remains on, badware remains off.