Now I think I've heard everything

[umpduck11]

Second game of varsity doubleheader,Fed rules.Team A
player caught in rundown between 2nd and 3rd.Defense does
a good job of rotating,as I move up from the plate.Defender
takes throw,and steps into base path to make the tag.
My partner is behind the play,and i call the out.Team A
coach comes onto the field wanting to know why we didn't
call "interference".(Yes,he said interference!)He then informs me that the defender had no right to block the basepath,saying the tag could be made from the side.I let him know defender had ever right to his position,as he was in control of the ball and was making a play on the runner.
Coach the tells me all I'm doing is allowing a potential catastrophe on the field,to which I explain malicious contact to coach.Coach looks at me,shaking his head as if I'm daft........