In contexts where [verb] is a transitive verb used in the construction...
It's [adjective] to [verb]
...it's largely a stylistic choice whether to explicitly specify the "object" of the verb (it) at the end of the utterance. Thus...
I like this game. It's fun to play [it]
...is syntactically valid with or without it at the end. But idiomatically, native speakers don't normally1 include it.
Note that although we don't usually include it in such constructions, this is nothing to do with the fact that the utterance starts with a (completely unrelated) use of "existential" it (as in It's hot today!, where it doesn't really reference anything at all; it's just an established construction). Usually, only non-native speakers notice and are bothered by such "repetition".
1 I may be overstating the case here. Perhaps it's safer to say Native speakers often don't include "it". There are probably some "guiding principles" as regards where we're more (or less) likely to include it. But even if that's true, the fact that I myself am not consciously aware of any such principles suggests learners don't need to worry much about it either.