The Subjunctivisor!

Does gustarle require the subjunctive?

Yes, gustarle requires the subjunctive:

Por ejemplo …

Me gusta que los niños jueguen juntos.
I like that the children are playing together.

The Subjunctivisor!  |  Subjunctive lesson

 Gustarle uses an indirect object to indicate the subject (as indicated by le attached to the end of the infinitive).