And I prefer my own kidneys instead of dialysis. Excessive use of protein exhaust your kidneys to the early grave with a high blood pressure and other symptoms triggered by using gear. That's why you should use a right amount, not just about and the some, but amount which you have calculated by your own condition. I bet you can list numerous builders with a kidney problems, and you will be joining in that bunch with that plain stupid attitude of yours, if you don't start thinking what you are doing. And it is just same if you don't use gear, it just takes somewhat longer time.
Consuming protein in excess (say 300 gm plus / day) will make your kidney work more by that much, but that doesn't mean everyone who does that is automatically or surely going to suffer from renal failure. For sure, if you already have a problem to begin with, eating too much protein will affect you adversely, but a healthy human's kidneys (and other organs) are far more resilient than we'd expect. It all boils down to genetic predisposition - case in point, known cases of young, healthy / fit people in their 30s or even 20s who go out for a jog, have a heart attack and die, while on the other hand we have people who chain smoke, drink and possibly abuse other substances living well into their 80s and 90s without dropping their habits while still being as fit as a butcher's dog.
What I'm saying is, you have no assurance that just because you watch and limit your protein consumption (or any other food / product) you will be immune to problems with your kidneys or anything else. If your body is going to have a heart attack while you are in your 30s (not meaning you in particular), it will happen, regardless of whether you workout and stay fit or not. Take bodybuilders for example - they all take tons of hormones and other stuff and in some cases, their body breaks down to the extent we see with guys like Tom Prince or Don Long. But then there are also others who look healthy and probably are, like a lot or perhaps, all the Mr Olympias from 1965 onwards till now.
Some guys go bald while taking low dosages of Decanobol or whatever the Hell it's called. Others like Jay Cutler and Dorian Yates retain their hair inspite of megadosing all the things they take / have taken. The best thing to do would be to not abuse the shit out of one particular food group or product or drug or a substance, but again, even that's not really going to guarantee you a long and healthy life. Besides, you say that taking 300 gm protein a day is too much, but what makes that 'unacceptably or needlessly high'? There are cases of people trying 4 gm / lb, although they are in the minority.
What your tolerance is for a certain substance or food is something you can only determine through hindsight. All the BS about 'acceptable or safe level of intake' is pure hogwash because it's just an indication of what the average or mean of a bunch of individuals is - it doesn't show you where you stand in the chart and therefore, what levels of intake you can tolerate without any negative repercussions.