My guess would because they’ve paid for the rights to cover snooker and are maximising value.

They’ll also know which sports deliver an audience and will attract more advertisers.

I quite liked their curling coverage when I watched it recently, it was clearly done on a budget, but was nice to see a minority sport (at least in the United Kingdom) receiving some coverage.

If I remember right Eurosport is operated by members of the EBU and coverage depends on EBU members getting the rights to coverage. Now as to what goes out on the commecial channels, that may be a different matter. As said, they may get rights to snooker, ski-ing and tennis, but on the commercial sat services they will show whichever gis likely to pull in the biggest number of viewers.