Flirting In Office..

Which you are not currently in.

This is not your problem. It’s their problem. Don’t make it your problem. Investing time is one thing. Ensuring employee comfort is also a dimension that they are not doing.

Personal reasons is a good enough reason. Nobody needs to know beyond that and there is no point bringing this up with HR. This place won’t suit you hut will suit someone who is thick skinned enough for this.

In which case what @Rihana said is an option. Turn a blind eye, put people in their place and continue until you get the training required.