I see this was asked a couple of times about three years ago and at the time the feature request was apparently denied:
- Filtering "hot" questions
- Can you filter out certain SE sites from the hot questions list?
- Blocking certain stack exchange sites
Is this still the case? If so, why? I have precisely zero interest in having certain questions polluting a list that I might actually find useful if I could at least tailor it a bit to my needs.