Artificers with the trap making feat can manufacture grenades at the trap making workstation but they can't use them. The grenades are class restricted to rogues.
This doesn't match my expectations of the "logic" of a fantasy world. I would have thought that the Artificer who is a master potion alchemist would certainly be a better chemist than your average pick pocket or kobold with greek fire.
Several of the artificer spells use "grenades" to hurl "cure" potions towards undead to damage them with positive energy. It is more in keeping with the image of that level of fantasy technology to allow the artificer to make heavy use of grenades.
If anything, the effectiveness/damage of the grenades should be enhanced when used/made by an artificer. I would like to see grenades improved overall so that they are more effective than repeating crossbows given the effort required for crafting; however, I would settle for even an enhancement line to artificers to improve their grenade damage similar to the way wand damage is increased.