I'm not sure how you are being punished. BA's soft rule applies to all: small bags under the seat in front. The intention is clear: free space for larger items, whatever the provenance, or ownership, of those volumes.

The emerging grievance in this intemperate thread is of a special case, passengers travelling with small items only but wishing to have those items treated as honorary larger bags to be consigned to the overhead bins.

It's an issue that I suppose could be addressed under the current system, but that would likely involve tags of a different design attached to small bags, designating their entitlement to overhead space. A nightmare, particularly as contributors to these threads have shown themselves adept at removing offensive tags 😄

An alternative is one I adopt. In business-class either negotiate use of the space under the centre seat in front; if negotiations fail, or I arrive late to the game, simply transfer any inconvenient item to the floor space between A and C, D and F after take-off. In economy class, if i am likely to be severely inconvenienced, i will find a space to wedge my backpack into the bins after the baggage.circus has done.

​​​​​​I can offer no solution to the sense of grievance that others are getting away with something they are not fully entitled to.