I agree, sort of.
If the result of the referendum had been remain and Parliament had chosen to exercise Article 50 anyway and leave the EU, I wouldn't have agreed with that.
Even though it was the law, and the procedures had been followed, it wouldn't sit right.
As for Gina Miller - read about her. She said before the case it was all about process, and after the case, when Parliament followed the result, wrote to Corbyn (Nov 18) saying what a disaster Brexit was and pushing for a people's vote. It is a long ish letter but worth reading, but what I liked best was the last line - "You have the power to both ensure an option to remain is included in the parliamentary meaningful vote, and if this vote results in an impasse, ensure there is a public vote, so the people of the United Kingdom can throw parliament a democratic lifeline to end this chaos." . Clever lady, fighting for her views, legally, and nothing wrong with that. But not an impartial advocate of Parliamentary sovereignty.