If these things [abortion / capital punishment] were brought in following a referendum and the democratic process being followed, I would be very sad but would accept this. I would campaign for these to be changed back, through the democratic process, not by blocking the democratic process which brought them in.
Then we reach a fundamental point of difference. I would not accept an abortion ban, or the reintroduction of capital punishment, and I would campaign not just to have the decision reversed, but I would actively support any legal means of blocking the legislation being implemented at all.
I couldn't just express sadness and resignation, and respectfully wait while laws are put in place and rights lost, and then express a wish for them to be changed back. That completely ignores the damage such legislation would inflict while I was waiting, politely and patiently, to have my say - which would probably be ignored, anyway, because, hey, there's been a referendum, don't you understand democracy/hey loser YOU LOST lol/how dare you question the people's will. And it's also a lot more effective to stop or soften flawed/damaging legislation before it's put in place.
You say we can set off down a track without thought for where it will take us, which worries me - and that's exactly how millions of us feel about Brexit. More accurately, we were set on the track by a complacent, careless idiot who promised a referendum, and we risk being led even further by someone who has consistently attempted to withold information, to ignore concerns, and to deny our elected representatives the chance to scrutinise and debate the details. Meanwhile, the right-wing press are also fuelling a divisive, dangerous rhetoric where anyone (whether politician, judge or citizen) disagreeing with Brexit can be labelled an 'enemy of the people'. It's a very ominous sign when participation in legal, peaceful democratic processes can be labelled undemocratic.