〜には当たらない
there's no reason to, it's not warranted
Verb dictionary form (驚く, 責める, 非難する) + には当たらない
Sign up free to review this point on a spaced schedule.
には当たらない says that a reaction like surprise, blame or praise isn't justified by the situation: 彼が怒ったのも、驚くには当たらない, "it's no surprise that he got angry".
The verb is a reaction: 驚く, 責める, 非難する, 感心する, 心配する. The first half usually explains why the reaction is unnecessary: it's natural, it's minor, or it's understandable.
It's formal and measured, typical of commentary and essays. It's close to には及ばない ("no need to"), but には当たらない is specifically about whether a reaction is deserved. 当たる here means "to be appropriate".
Compare にかたくない, "not hard to (imagine)".
Examples
彼が怒ったのも、驚くには当たらない。
It's no surprise that he got angry.
子どもが失敗しても、責めるには当たらない。
There's no reason to blame a child for failing.
その程度のことで、感心するには当たらない。
Something like that is nothing to be impressed by.
よくあることだから、心配するには当たらない。
It happens all the time, so there's no cause for concern.
状況を考えれば、彼の判断は非難するには当たらない。
Given the situation, his decision doesn't deserve criticism.