I agree with you entirely Kalavo, you have to then make a decision on what else could go wrong and what you could do to mitigate such problems, this is the job of all Pilots irrespective of the law, to gather all available information and then make the safest decision based upon all available information. A broken fuel gauge itself isn't necessarily a fault that could indicate other further problems. As I stated though this is why you should bring it up with your Chief Pilot and/or HAAMC and/or a LAME, as I stated any defect whether major or minor should be inspected and then determine its level of effect on the safety of the aircraft.
My last company which also used MELs had this particular one written and stated that you could depart with one not working as long as the other was functional, you have and used a calibrated dipstick to determine fuel levels whenever practical and that fuel on board meets regulatory requirements.
Whoa, hang on a second there, In this situation your MEL told you to carry an extra hour of fuel and you couldn't depart without using a calibrated dipstick to determine fuel on board and have the other fuel gauge functioning. But how can you be certain the other fuel gauge is function properly? it might be going down as expected but what if it develops a fault and is actually overreading whilst the fuel tank is leaking? What if that Fuel Flow/Totaliser is also overreading and giving you false indications? What if you didn't realise you were on sloping ground when you dipped the tanks and therefore it isn't accurate? Yes you took actions to mitigate the risks but in the end pure bad luck could bring it all down, regardless of MEL or not. Theres always risks in Aviation, to believe that simply following all rules and regulations will always keep you safe is folly to say the least, but this doesn't excuse not doing everything reasonably within your power to mitigate all known and expected risks irrespective of what an MEL or rule or regulation tells you.
Honestly Kalavo, I think you and I are on the same page, I'm just trying to make my own point that MELs aren't the be all and end all, there just another layer of safety that common sense should, but can't always, provide. And I don't know about you, but certainly most S/E VFR Aircraft i've flown, I wouldn't really trust their fuel gauges, the IFR Twins were always great though, but they were of course maintained to a higher standard.