Although its minor, I don’t think a creature made of fungus should drop tainted vegetable bits. Instead, wouldn’t it be more reasonable to drop something more fungus themed, either fungus coated flesh (for fungal zombies/insects) or fungus chunks. Both would incur the fungal infection when handled without enough protection or eaten raw, but when thoroughly cooked and cleaned somehow, you would get a usable, edible chunk of mushroom (flesh for infected zombie/insect). You could then craft these mushroom chunks, along with clean water, to get mushroom soup, or just eat cooked.
I read from http://smf.cataclysmdda.com/index.php?topic=2113.0 that fungaloids are going to be more focused on spreading, rather than using the mindless zombie way of trying to kill you. Near their fungal bloom, they may defend their fungal spire, but otherwise, if their goal is to spread, why wouldn’t they just vomit spores onto you and then walk away, spewing spores as they go? If they die, it is fine, for you are now a spore carrier, and since you regularly vomit spores, which then make young fungaloids which spread even further, that means that they have spread.
If you butcher a fungaloid, it makes sense that there should be a decent chance to either transmit the infection unless you have hand protection, or to release spores into the air. This would balance the otherwise ease of getting food from fungaloids.
If they tried to infect you, but you were immune via either a mutation, bionic, gas mask, whatever, they would be smart enough to realize that you are immune, and just start attacking you; otherwise they would be very easy to kill without any repercussions.
A balance could be that ordinary fungaloids could be ‘mindless’ and don’t respect the mask, but zombies and things do, and if they ever added treants as an enemy, near the tower fungal treants would hang around instead of pure trees near the core, but would go berzerk when you tried to get too close or burn through them, and they could act as both normal trees, being a good long-lasting fire source and/or butcher into fungal trunks/logs and some mushrooms when killed normally. They are also smart enough to know when you have masks/guns out, so they might group-up if you have a gun but spread and surround if you have a flamethrower. This would balance a light-fungal which could be useful for surviving (nutrition/clothes), medium-fungal which is not too useful but more challenging, and harder-fungal which are very dangerous and provide some kind of non-standard loot, while not being overtly aggressive or hazardous to see.