I'm claiming that three games do not constitute a sufficient sample size to proclaim Columbus to be "the" favorite to win the 2019 Stanley Cup, and that any person doing so is placing far more weight upon these three games than is reasonably warranted.
The difference between Columbus and the 2nd best team in the entire league after Tampa was 9 points.
They were tied for 6th in the league in wins and ROW, just two off of 3rd in the league in both categories.
They added multiple significant impact players at the deadline, so we know their full season point totals are not representative of the current quality of the team.
After a rough patch with a bunch of new players (common), they secured a playoff spot at the end of the year with a great run, going 7-1 in their last 8 games, with 3 shutouts, while outscoring their opponents 35-14.
They are now up 3-0 in the series against one of the best teams in the history of the NHL, outscoring them 12-5.
It's a bigger sample size than 3 games, and context matters. Maybe you're not placing enough weight on what we've seen. It's not unreasonable to have Columbus as the favourite, especially with how wide open the playoffs are this year.