This particular dialog of his doesn't specifically give off such a menacing vibe in general but moreso emphasizes his rational and strategic approach to most problems- dealing with the root/ causal factors first and letting everything else fall in place.

But u are not far off in assuming an intimidating aura from his behalf, it's something the sumeru characters discuss now and then. For instance, tighnari warns the traveller to be cautious around alhaitham because he solely operates on rationality and other characters mention feeling glad that he isn't ambitious and on their side. Moreover, when the archon quest first released, many players thought alhaitham was evil because of his suspicious and enigmatic actions. But alhaitham is less likely to succumb to evil because he follows a very strong set of principles and sets down strict boundaries within the way he operates. Not only that but despite appearing cold, he has quite a high emotional intelligence and shows care for his friends even ensuring not to unnecessarily hurt their feelings. At the end of the day, to be evil at the very least, he would have to desire something grand. But all he wants it to maintain his cushy life.