無理(むり)もない(to be) natural, (to be) understandable

いじめられた子供(こども)が泣(な)くのは無理(むり)もない。

It's natural for a bullied child to cry. {(to be) natural, (to be) understandable}

彼(かれ)は浮気(うわき)されたのです。怒(おこ)るのも無理(むり)もないです。

He was cheated on. It's natural and understandable for him to be angry. {(to be) natural, (to be) understandable}

ずっと無視(むし)されたのならいじけるのも無理(むり)もないです。

If you've been ignored for so long, it's understandable that you'd feel upset. {(to be) natural, (to be) understandable}

半年(はんとし)で二(に)十(じゅっ)キロも太(ふと)ったのなら彼女(かのじょ)から振(ふ)られるのも無理(むり)もない。

If he gained 20 kilos in half a year, it's understandable that she broke up with him. {(to be) natural, (to be) understandable}

僕(ぼく)は彼(かれ)を結婚式(けっこんしき)に呼(よ)ばなかった。彼(かれ)に距離(きょり)を置(お)かれるのも無理(むり)もない。

I didn't invite him to the wedding. It's understandable if he wants to keep his distance from me. {(to be) natural, (to be) understandable}