Agreed on almost all of these, except:
If your team lost because of a tunnel, your team was not strategizing very well.
It's very unfair to say the other team wasn't properly strategizing while using the tunnel-win as proof of that. Let's be real here, while tunneling is a valid tactic, a large chunk of the time it's used as a deus ex machina in rounds that last long and both teams are good. If your flag gets grabbed by a tunneler, and most of the other team's players are close to their base, you killing the flag grabber becomes virtually impossible.
Even if you manage to kill all of their teammates at the base, they'll respawn and keep hitting you, and if you manage to kill them again this time, the next time they respawn they will most definitely manage to kill you and the rest of your team, slowly. And since basically no one will be left waiting to kill the flag carrier, he/she will arrive at the team's base peacefully and capture the flag. Unless of course one person managed to hide close to their base. In that case, he/she will probably get killed quickly after jumping out of the hiding spot, considering that all of the other team's pros will be at the base.
This is one of the reasons I support more features that encourage teamwork and make it easier, if you guys manage to hide in the same spot until the flag carrier arrives the chances of you all killing him/her become much much higher.
So basically, a team has the advantage of being close to their base, thus pretty much fully killing off the other team (albeit pretty slowly) who are waiting for the flag grabber to arrive so they can kill him/her. Since there's a lot of panic during the "person has grabbed your team's flag" moments, the team's going to be very panicky and disorganized, which as stated before, will result in their deaths. This can be easily fixed by adding more features that make teamwork easier, however the best proposed idea is impossible to do in Minetest as of now.