It's much easier to be it if you see it.
Anyone who doesn't feel they fit naturally into the demographic of whatever activity will feel self conscious.
Maybe like they're not welcome, or as if they have to prove their worth to participate.
If those from the dominant culture.. In the case of cycling pale and male, don't recognise this, and actually make an effort to not be part of the problem, then they are signalling that they don't really give much of a sh*t about inclusiveness.
In the case of many women, its also a case of giving themselves permission to have time off to persue a leisure activity.
This isn't helped by them often being expected to fulfil more of the caring roles, on top of paid work, with the triple whammy of often being paid less, so having less money to spend on kit etc.
Guys are generally better at ring fencing, and feeling entitled to their leisure time, either alone, or with their bros.
Add on top of that the heightened risk (perceived or otherwise) of hassle by 'bad guys' against women, or poc.
It all adds up to an unhealthy mix of disincentives.
Inclusivity projects can help to a certain extent.
But if that's not backed up by a general change of attitude in wider society, then participation from non trad groups will be slow to increase .
Everyone should feel as entitled to take up relative low cost activities, such as cycling.
The reasons they don't join in, are complex, but a good starting place to find out why, is to ask those groups themselves.