Welcome to the forum Mr. Macguyver. After skimming your post, and looking back over more experience than I care to mention, all I can really say is... I feel your pain. You have hit one of my hot buttons, but its late and I will forego starting yet another opus at this time. Suffice it to say that you have two choices: you can "fight the good fight" and risk ending up bloody and disliked by all the old farts, or you can simply do your best to try to learn what their system really is (not what they say it is) and just try to catch glaring drawing errors, within that system. Standards are a wonderful thing, but I think too many young folks place way too much importance on them. If its ugly but works, it works. You will get much better results in the long term after the folks there see you as part of their team, rather than the new guy that's there to "fix" them. Then when some problems do start to come up repeatedly, you can get them involved in finding root causes, like maybe dimensioning to fictional features, or from multiple datums. Let them suggest the solutions. If they can feel like part of the solution, rather than the source of the problem, they will be supporters of the changes. Hang in there, and pick your battles very carefully. One day you will be the old fart.
One other bit of advice that has served me very well over the years: a marketing consultant I once knew told me that the purpose of good communication isn't to make sure you can be understood. It is to make sure you will not be misunderstood. The same applies to drawings. Just because someone can make a part that works from the drawing, doesn't mean the drawing is right. The drawing is right only when the part cannot be made incorrectly.