What happens is that, instead of taking the music as it stands, the performers are always striving to make the link with the autobiography: here is a phrase and we must play it as passionately as possible because, hey, this quartet is 'about' the passionate relationship with the young woman. The more strenuously you try to link the music with the life, the more you tend to distort, to twist the music to an extra-musical program. So they played the whole quartet with this wild abandon. The music may have been inspired by the romance, but it is not necessarily, if it is a good piece certainly not, limited, hedged in, by the events in the life. The flow of the music has its own character and stamping all of it with a conception taken from the composer's autobiography is to fail the take the music as it is, with its own logic. Here is the first movement from the quartet:
The challenge with music this disjunct, with so many contrasting sections in different tempi, is to tie it all together and to do that you have to see how the structure underlies the whole. What motifs connect the sections? How does the harmony give direction to the whole? And so on. But if you are focused on making it the soundtrack to an imaginary movie of the composer's life, well, it may be passionate, but wayward as well. And that was my impression of the performance. Too much awareness of the inspiration and not enough of how the music was actually put together.
And to go back to the Beethoven for a moment, yes, he is in the classical tradition of Haydn and Mozart, but that does not mean his music is genteel and refined.