既然是介词，to 接名词正常，接动名词也正常。

If you commit yourself to something, you say that you will definitely do it. If you commit yourself to someone, you decide that you want to have a long-term relationship with them.

commit oneself to something：承诺、致力于某事（something 可以没有动词意义）

commit oneself to doing something：承诺、致力于做某事

如果to 后面的名词词义明确，那么，动名词就可以省下不说。如网友的句子：

They were reluctant to commit themselves to （giving）an opinion.