EDIT actually wait
Those two platfoms are perfect for shooting and jumping off of, unless the person spawncamping is deliberately shooting up, their line of fire is going to be right down the middle slope
On the left side there's a box placed that can be shot and then jumped upon and squid..ed...across, getting you out of the danger area. Thiis is ALSO out of line of enemy fire, and there's no way they can focus on both these patches of land and you at the same time, even if there's more than one inkling harassing your spawn. The only way to cover that box in their ink is to either get on that platform (which would involve coming right in front of your spawn, turning around and shooting at it) or shoot towards the sky and have patches of ink land on it, which could easily get covered with your own ink.
Of course no one used them because it's day 1, hour 1 demo playtime, but I feel when people gain proper map awareness, this issue will disappear.