I think there might be some reasons to be optimistic. Any civilization that might notice our signal and decide to interact with us has with us has existed much longer than our own civilization with high probability. Thus, there is more evidence of long-term stability in such a civilization than our own. With stability comes the potential for experience, with experience the potential for wisdom.
How would you expect a society that is extremely stable would deal with an incohate civilization? I think it's at least plausible they would want to stifle potential problems in the cradle, so to speak.
Why would you believe they’d have our extremely temporary set or morals? Human empires have lasted for thousands of years and the one thing that binds 99% of human history is soul crushing enslavement of each other.
I watched a short movie (an episode from the Outer Limits? It was ~20 years ago) about some army rangers who stumble upon, track and ultimately kill an alien.
When observing it closely afterwards, they realized it was an alien child sent to Earth on some kind of children camp.
The primitive livings on that planet killed the child. The parents were not happy, blew up the camp (and our planet).
A relativistic kill shot would take out a lot more of Earth's biosphere than humans are likely to. If we kill ourselves, bacteria and cockroaches will live on. Not so much, if Earth is vaporized to make way for a hyperspace bypass.
On the upside, the bypass is very splendid and worthwhile. Even ignoring something as extreme as the Dark Forest theory, it still seems like a questionable policy. A more conservative aim would be to want to maximize development time against the risk of discovery, ideally ultimately finding yourself in the role of observing without being observed. The history on our planet of first contact between disparate groups of humans should be illustrative. Even when people had good intentions, the unforeseen impacts could be enormous; I’m thinking of smallpox, and even the history of coexisting Neanderthals and Homo Sapiens. Maybe aliens are totally different, but it’s a hell of a thing do, assuming they would be more benevolent.