You can certainly use the present tense too, but it doesn't mean you can't use "will" as the original sentence does.
"will" doesn't automatically mean the future tense. It can mean one's intention and yes, habits and tendencies too.
"Boys will be boys" for example doesn't mean the future but that they tend to be, i.e, they habitually act like boys.
On Dictionary.com, #7 meaning of "will" shows: "am (is, are, etc.) habitually disposed or inclined to:".
So I say your example is fine as it is written. There are more than one ways to express the same idea.