Recording in one's own home is exempted under the GDPR[0].
I suspect something broader was involved here.
[0] Article 2(2): "This Regulation does not apply to the processing of personal data [...] by a natural person in the course of a purely personal or household activity"
A prime example where GDPR would apply to a security camera in your own house would be if that camera was used to record renters (including short term rentals e.g. AirBnB) without their knowledge.
For example, I recall reading about cases of renters finding out that the landlord has installed hidden cameras in the bedrooms and showers.
