In essence, the Avengers were still a righteous organization. Though they never went easy on enemies, nor did they follow any No-Kill Rule, when faced with a life that had only just been born—even if that life looked like an adult—they genuinely found it somewhat hard to make the kill.
Even if Adam was an artificial being, not at all life as the Avengers understood it, the Avengers still found it very difficult to harden their hearts and kill him.
However, simply leaving Adam alone or taking him back to Avengers Base was not very appropriate either. After all, Adam had been created by that mastermind who had yet to show himself. For all they knew, Adam might have some special method on him that they could not detect.
If they really took Adam back to the Avengers, it would be no different from previously bringing those experimental devices back to the Avengers. Both could potentially lead to intelligence being stolen.
But handing Adam over to the Guardians of the Galaxy was different. The Guardians of the Galaxy did not operate on Earth, so they could not obtain much intelligence regarding the Avengers. Moreover, Star-Lord had ties to the Avengers as well. If there really was some problem with Adam, Star-Lord would be able to contact the Avengers at once.
Besides, at the current stage, Star-Lord had also awakened divine power. Even if Adam really had some kind of problem, Star-Lord was not without the strength to fight back. After all, Star-Lord was not some brainless person like Drax. He would definitely remain wary of Adam.
"Let's go. Then we'll board Star-Lord's spaceship directly and head to the Saiyan and Ego first. No idea how their battle's going after all this time. To be able to fight a Saiyan for