Esa-Pekka Salonen is setting up a 'straw man' argument, so that he can defeat it.
When Berlioz was new kid on the block, doubtless his innovations were criticised simply because they WERE innovations. Innovations generally are! And there may be people even today who feel the Symphony reached its height with Beethoven, and subsequent use of the term for less firmly structured music was sacrilege. (Though they might have to admit the first cracks appeared with the programmatic elements in Beethoven's own 6th Symphony.)
But it's not a widely-enough held opinion to be worth worrying about, other than as a rhetorical device - and that's all that Salonen really uses it as.