I'm not saying that there's no opposition, I'm just struggling to understand why she's moaning. Gina Miller's actions, whatever the motivations behind them, have ended up with establishing a constitutionally-valid approach to Brexit, which is hardly a bad thing. Nor should it be unreasonable for those who wanted us to remain in the EU to still have a voice -- a role in shaping Brexit, at least.
At about this point NJ would say something like how the referendum was a vote to leave the EU. Nothing more, nothing less. Agreed -- but then the question of what leaving the EU will mean, what positions we should or aim for, what trade and political deals we should reach, are all open to question and debate. An "opposition", in the sense of people disagreeing with Theresa May's objectives on this, is welcome to all, surely? At the very least, it forces her to explain and defend her choice of stance.
At any rate, the motives for calling the election are dubious. I imagine that Theresa May was more scared of the opposition in her own party than of Labour. Although then, which wing of her party was she wanting to challenge?