Zombie Villager Infection

 Most people who trade with villagers know that infecting and curing villagers is essential. However, it is set up so 50% of the time on normal and 100% of the time on easy, the zombie just kills the villager. I for one find this really painful, and it makes no sense. Why should it be harder to cure a zombie villager on the easier modes? 
My idea is that mojang either adds a way to guarantee the villager being infected, or makes it 100% infection rate across all modes. I don’t know if it is just me, but it would be great to save having to breed my villagers constantly because I tried get better trades.