ubiquitin,
you misunderstand; Doomsday feel that the CRC, entire US Government, entire world wide medical profession and most of the general public are part of the conspiracy against Anti-Vaxxers. She has never addressed why she does not follow the Da’as Torah except to say there are unnamed rabbi that are anti-vaxxers despite the vast majority are require vacations; i.e. we follow the majority which she may remember from her Bas Yaakov days.
There are anti-vaxxers that are
1) Anti-establishment
2) Anti-science
3) Anti-medicine
4) Anti-personal physicians
5) Unwilling to follow the far majority of Da’as Torah
6) Are placing their personal views above Halachah