Why are dbSNP indels excluded from indel realignment?
According to the known variants documentation (https://software.broadinstitute.org/gatk/guide/article?id=1247), only Mills indels and 1KG indels are recommended for indel realignment (RealignerTargetCreator and IndelRealigner). Although dbSNP contains indels (including 1KG indels) and is also in the bundle, it is not recommended. Why not? Is there a problem with using too many known indels or that may contain too many false positives?