Newbie here. It makes sense that "ài" means "love" in the context of hobbies; you're doing what you love. What does "hào" mean here, though? Is it just a strange pronunciation of the standard "hǎo"? Or is it more like "hào" is used to mean "lovely"? Thanks!
When a character have multiple similar pronunciations, such as 好 with different tones, it can means different part of speech for the same/similar concept. This phenomenon is called 四声别义. For example:
好(hǎo，上声): adjective. good.
少(shǎo，上声): adjective. few.
少(shào，去声): noun. young people.
骑(qí，阳平): verb. ride.
骑(jì，去声): noun. rider (on horse).
教(jiāo，阴平): verb. teach.
教(jiào，去声): noun. teaching.
In your question, 好 of 爱好 is a verb. The meaning is similar to 爱. Therefore, people combine these two characters to mean a verb, to like. 爱好 can also be conjugated (called 活用 in Chinese) as a noun, means hobby.