They're not. But the reason they're not safer, is because the average recreational pilot is generally lousy at those skills on an on-demand basis, especially when in IMC. It's politically incorrect to say it, but it's true. They're simply not consistently exercised enough to deal proficiently for such an eventuality, as a demographic. At that point they're no better off than the guy trimming the single engine bird to a dead stick off-runway "landing", in fact worse off as they either Vmc it or crash it on its temple.
I'll be completely honest with ya. Single engine approach to single engine go-around in IMC single pilot is straight up WORK and a bad enough day that would put most commercial operators on sweat alert. Those cocky enough to deny it are lying to ya. No way I'm not doing that recreationally. Can I do it? Sure. Do I want to do it? Hell no. I got "flip flops on my mind" when I fly man, this stuff is supposed to be fun on my days off.
Ways to mitigate general suckage at multi-engine emergency for the weekend warrior? 1)Don't do IMC on it. 2) Fly well undergross. 3) Takeoff and land from retarded long runways. Presto. Even the most cockeyed dummy can keep it coordinated enough to swing it back around VMC, chop the good engine and land it dirty side down, if all you do is stick to #1. You'll probably live long enough to sell the thing too.
We have a couple twin contributors on here who probably fly enough to keep themselves honest in IMC or short departure engine loss. Do I think they're reflective of the twin owner/operator sub-demographic they belong to? Nope. And if they're honest with themselves they'll probably admit it.