What is it with players starting defend mission before actually placing any builds?

I recently played a Ride The Lightning mission where another player started the mission activation vote, no more than 60 seconds after loading in and they didn't even place a single build, much less a single trap, and 3 other players voted yes; with me being the obvious outlier. I placed several Anti-Air traps, to deter the lobbers, and after the 1st wave had ended, I went to clear out the map for the Exploration Badge, but they immediately started the vote again, and by the time I got back during the 2nd wave they had already gone below 80% of the van's health, effectively losing out on the bonus badge we could have gotten.

I left before sticking around to see if the mission was a failure or not, and after playing another mission, I then loading back into the same Ride The Lightning mission, and this time I was matched with a much more efficient and cooperative team that actually helped in clearing out the map, helping with storm chests, as well as activating team boosts. Not to mention, actually placing traps, and decent build. Even after waiting a bit before starting the mission, we still won the Bonus Speed Run Badge. Generally, a much more pleasant experience.

Has anyone else encountered these overconfident players who start the mission right away without any form of preparation or planning?

I'd much rather enter a mission with players who don't know how to use Broadsides properly, because at least that can be easily solved with a simple wall placement and typing in the chat that "Broadsides don't work without a wall for them to bounce off of", because at least those players are trying and willing to learn to be better players, as opposed to just not giving a damn and jeopardizing the mission.

I know it's just a game, and I'd like to apologize in advance if I'm coming off as overly heated, but it's just straight up confounding to me how reckless some players can be in this so-called "cooperative team-based" game.