I might not be a cyclist, but I do a lot of walking, including hillwalking, so the implied assumption that anyone not on a bike is unfit is a bit daft.
Poppy's experience is all too common - I've been forced off bridleways by some very aggressive cycling. Of course some cyclists have been polite and thanked me if I've moved out of the way for them...but a worryingly large number have barged past me as if I'm invisible, even on very narrow paths.
Sorry all you cyclists who don't want to hear this, but I'm not going to lie about it, I'm telling the truth - I'm sorry you don't want to hear it.
Cyclists shouldn't be on the pavement. That's an inarguable fact.