‘Individualism’ is maligned by both Left and Right. The Church of England attacked it in its 2015 pre-election report.
The Oxford English Dictionary gives this as the primary definition for the word:
independence and self-relianceI am not aware of any evidence for a correlation between (a) independence/self-reliance and (b) behaving with less consideration. Conceivably, there is a negative correlation.
The Prime Minister should refrain from reinforcing social myths. Perhaps by “individualism” she actually means indifference to family, arising from reliance on the state. If so, she should use a different word.