Старики can be used to refer to 'old people' in general, when speaking about both old men and old women. 'Old woman' is стару́ха, but it feels even less polite than 'старик' somehow.
In general, I think «стари́к» is not too polite either. I'd usually say «пожилы́е лю́ди», «лю́ди в во́зрасте» or probably even «лю́ди поста́рше» (although this one is probably too euphemistic: 'people a bit older') instead. Even «ста́рые лю́ди» sounds a bit more polite than «старики́».
My variant was "The elders love to read". I didn't report it as I'm not sure whether I'm right or not. The Longman Dictionary says about elders: "a social group who is important and respected because they are old". I guess it's not completely synonymous to "старики"... Though, people in russian villages can say "старики" about the oldest people living there, who know a lot and in general are respected. Would "the elderly" ("people who are old" - Longman again) work better? Would Duolingo accept that? Has anyone tried? Should "elders" work too?
There's a reduced but noticeable А after ст.
The real problem with this sentence is the intonation: it is seriously wrong. Also, the pronounciation of Б is unnatural.
Only when they're stressed. So, in лю́бит /'lʲubʲɪt/ and лю́бят /'lʲubʲɪt/ the difference is not audible (except in extra-careful pronounciation or some dialects), but in боли́т /bɐ'lʲit/ and боля́т /bɐ'lʲat/ it's audible.