SharePoint create/add visitors to userprofile

I am using LDAP-filtes to import user profile. The user in same unit appear to userprofile aften they are given vistior perisson to internal sharepoint site. These users dont have access to the portaler.

I have to run nonimportedobjects and dele each and every using powershell. some of them can not be deleted. so have to delete manuelly.

Why these profile are being created in userprofile as they just have visitor access to envirement.
any possibility to avoid them to be appear in userprofile?