Cycleway 27 is not hidden on a footway, any more than it is hidden on a highway (like the adjoining Middleton Road).  Cyclists who want to follow C27 can do so on the other Map Layers - CyclOSM / Cycle Map.

The logical conclusion of your argument would be that the 'on the ground truth' (of the painted signs) should be checked with a lawyer before being mapped.

This path has a clear (to me, subjectively) vibe of a footpath rather than a cyclepath.

If you change it back, I won't change it back again - but to guard against anyone else doing so, you might put your point about the reason to ignore the on-the-ground signs in a note tag?

I've long thought there should be a multicolour red/blue way on osm.org for cycleways that are explicitly walkable and footways that are explicitly cyclable - but last time I looked at the code, all elements are monocolour only.