This is a valid point, and I'd take it a step further. Not only are we not well suited to speculate on the nature of life "at large", we're even less suited to speculate about the nature of intelligent life (whatever that even means).
On the other hand, should we encounter sentient life, it certainly is not difficult to imagine hostility or callous indifference -- from either party. Particularly if said encounter is not on our terms.
And as profoundly exciting as the prospect of meeting alien life would be, I'd much rather it occur sometime after we've grown up a bit, ourselves.
So we should not speculate at all? That's a rather dull outlook.
I certainly agree that our dataset, re: "life as we know it", is horribly limited. Likely to the point of uselessness. But hypotheses are the foundation of any science, after all, and what little we do have to go on suggests that competition/predation, rather than cooperation/symbiosis, may be a more reasonable expectation.
But perhaps not. In which case, we'd be very lucky to encounter such an enlightened species.
Actually, after you've been struck by lightning once, your chance of getting struck by lightning again is the same as getting struck by lightning in the first place.
On the other hand, should we encounter sentient life, it certainly is not difficult to imagine hostility or callous indifference -- from either party. Particularly if said encounter is not on our terms.
And as profoundly exciting as the prospect of meeting alien life would be, I'd much rather it occur sometime after we've grown up a bit, ourselves.