Some people cite the argument, "We must not preemptively attack someone, or else others will preemptively attack us".
Preemptive attacks are attacks which are designed to prevent someone from hurting you, before they actually do it. It's defensive: it's only done when there's a concrete threat.
First of all, to say we shouldn't do preemptive attacks means that we must wait for someone to hurt us before we can defend against them.
Second, to attack us using the justification of preemption is ridiculous. We don't just go around attacking people for no reason. We're not a threat. If people deal with dangerous threats, that's good. To think that we're a dangerous threat is crazy.