obstruction or interference?

Question
In a 15-U girls fastpitch softball game tonight we had a very controversial call made by the umpire and I want to know if the umpire was right or not.  With runners on 1st and 2nd, the batter hit a deep ball to left field.  The runner on 2nd rounded 3rd and headed home.  There was no play at home as the outfielder had not yet gotten to the ball.  The catcher was completely straddling home plate with her body, forcing the first runner to slide in between her legs.  The catcher never got out of the way to allow the first runner to come into home plate standing up, she forced the slide to have to occur, and then after the slide she basically blocked the first runner with her body so that she could not get out of the way in a timely manner.  The first runner literally had to slide her body out from between the catcher's feet.  The runner from 1st base rounded 3rd and was sent home while the first runner was still trying to get out from between the catcher's legs.  The ball was thrown in from left field to make the play on the second runner, but was thrown well over the catcher's head.  The umpire called the first runner out effectively ending the inning and the game (third out, home team) saying that she had interfered with the play at home.  However, I would have called it an obstruction by the catcher in the first place and awarded both runners with home plate.  The first runner should have never been forced to slide because the catcher cannot block home plate when there is no play.  What is the correct call?  These teams follow ASA rules.

Answer
Hi Denise,

I've had to read your question a # of times to try to figure it out.  I don't understand some things.

1)  R 1 is not forced to slide, while she cannot remain upright and "crash' into F2 she certainly has the right to free access to the plate,,  Remaining upright she could use her body to get to the plate while drawing the obstruction call.

2)The runner from 1st base rounded 3rd and was sent home while the first runner was still trying to get out from between the catcher's legs.  

Why is this taking so long, is F2 hindering R1 from getting up?  If so she has the "right" to get up and get out of the way

3) The ball was thrown in from left field to make the play on the second runner, but was thrown well over the catcher's head.  The umpire called the first runner out effectively ending the inning and the game (third out, home team) saying that she had interfered with the play at home.

R1 cannot be called out for interference they have already scored.  

There can be no interference because there was no play, the thrown
ball went over F2's head, unless R1 had F2 by the jersey holding her down

However, I would have called it an obstruction by the catcher in the first place and awarded both runners with home plate

Probably so would I

The first runner should have never been forced to slide because the catcher cannot block home plate when there is no play  

Correct but R1 didn't have to slide

Mark