Yes, Kent every landing in a sailplane is dangerous, just as every skydive, scuba dive, shuttle launch, etc is dangerous. The risk involved in sailing is, in my opinion, less than that of gliding in a multi-engine airplane.

Just look at the differences:
A sailplane is designed with high glide ratio wings that offer unparalleled gliding distance versus the altitude lost. A sailplane is very light, given that it carries no fuel and often no more than two people

A multi-engine airplane with no engines operating has a very low glide ratio, and a very heavy frame. Twins carry more passengers than gliders, even though only one or two may be aboard. Twins on average would be expected to carry more payload than gliders, since you would expect to take twins to other airports (chocks, extra engine oil, big flight bags, luggage, tie-downs, etc). In general, comparing the performance of a multi-engine airplane with no engines operative to a sailplane is probably like comparing a feather to a rock.

As to the factor of fuel flowing to the engines during the landing, assuming the point is to reduce the possibility of fire, the fuel is kept in the wings. Wouldn't you expect most of the impacted area of the aircraft during a gear up landing to be either the belly or wing-tips? The fact that we don't hear of tragic deaths from belly up landings should be a testament to the safety of the airframe in this condition.

I guess it all comes down to what feels right at the time, personally I like having a backup plan!