Knuckles_How do you not know the path of the loose cannon? It's easier to see and has a shorter range. And 85% of the time you get hit by a loose cannon it does 60, not 100. Don't say "they only do 100 damage" like that isn't the highest mid to long range damage in the game besides the lucky double donk
It's true that a demo will be weaker in a 1v1 while using the loose cannon and that it is mainly used for mid-range and you're pretty defenseless at short range. But I think you would also agree that most demos that find themselves in a 1v1 or allow themselves to be over extended to that point will generally lose that 1v1 and are already pretty defenseless. Most demos tend to play mid/long range spam and avoid unnecessary fights/damage taken, furthering the advantage of using loose cannon. The pipes also have a smaller splash radius and are easier to dodge while coming through a choke, whereas the donks themselves are just as easy but the splash radius from them is much greater. So although it might only do 60~ damage, it's more common to get hit by them and lose 40-60 hp on 2-3 players coming into a fight instead of being able to dodge the pipes and the only way to get hit by them is to take a direct 100 damage pipe or walk into rollers which is far less common.
Also disregarding all the damage/defense issues that are being spoken of, my main point is that it doesn't even fully follow its own weapon description. It will randomly launch people forward after getting donked. The weapon is undeniably broken in that sense and needs a fix.