No it is not. Otherwise good people would do bad stuff all the time - but they don't. Just look at most people most of the time. It requires the dogmatic and dehumanising and intolerant elements of irrational ideologies.
You are looking at the wrong scale. Due to the diversity of circumstance and personality, the collective is far more relevant than the individual. Good people do indeed do evil things all of the time and always will because it is a part of our collective nature.
"Rationalists" like Weinberg have a tendency to view violence as an 'error' hat can be fixed rather than an evolved capability that is as intrinsic to our collective nature as altruism and kindness.
You are also making the mistake the kind of mistake that Weinberg makes thinking it requires "dogmatic and dehumanising and intolerant elements of irrational ideologies" to make good people do evil things. That is why I provided Koestler's quote about it really being the consequences of the same aspects of our nature that can drive positive behaviours.
One major factor that drives good people to do evil things is empathy (for those deemed oppressed).
Many people who supported the Iraq War were centre-left liberal interventionists. Christopher Hitchens basically supported it based on his Secular Humanist values.
It's obviously not simply "dogmatic and dehumanising and intolerant elements of irrational ideologies" that can be used to legitimise violence. Throughout history, people killed in the name of "Progress" far outnumber those killed in the name of religion.
They are capable. Maybe not uniquely, but they manner in which they do it is somewhat different to political ideologies.
That assertions would first require you to be able to differentiate between a religion and a political ideology in a meaningful way, and then demonstrate that they are indeed different.
Neither of which you are likely to be able to do.
If you want to try, explain how militant nationalism and Soviet Communism are fundamentally different from 'religion' in the way they affect people.
Is it? Could you provide some examples?
The obvious examples would be things like scientific racialism, eugenics and social Darwinism that were widely supported among the scientific rationalist community, even by the progressives of the day.
Even more harmful would be the impact of Malthusian views on human population that drove policies that exacerbated famines that killed millions.
Science and reason are value neutral, which is why many Enlightenment ideas were profoundly illiberal. Once you deem something 'scientific' then it can be used to justify causing harm because such harm is 'for the greater good', 'inevitable', etc.
Seems like Weinberg struck a nerve.
It's more contempt as I'm not a fan of hypocrisy or bigotry based on irrationality and ignorance.
I'm an atheist so I have no emotional need to defend religions (although, unlike many atheists, I have no emotional need to disparage them either). Anti-theists tend to be remarkably self-congratulatory on their own rationality, so when they peddle naive and irrational misrepresentations it is fait to point these out.
TBH, your objection smacks of whataboutery.
Yes, some political ideology can also get good people to do bad, but that does not exonerate religion from the same crime.
"Yeah, I did all those murders your honour, but my neighbour did some as well last month".
Then you are badly missing the point.
To point out that Weinberg fundamentally misunderstands the issue in question is not remotely comparable to "whataboutery".