Except the small amount of armor they do get is null and void as even with said armor they go from dying to a wet noodle slap, to dying to two wet noodle slaps.
Juggernaut or Jordis Golem, don't count, as they're not the normal common enemies you would be fighting, specfically The Jordas Golem.
Now don't get me wrong, Corrosive Projection is amazing and incredibly good, but the way people act like it's a must is kinda of ridiculous, as it only really is needed/at it's real potential when you're doing endless missions.
The highest level you're going to commonly be against when would be around 60-100. Not counting endurance runs, since the majority of the community don't even do that. And at those levels your weapons do just fine, especially against Infested or Corpus, sure the Grineer units are gonna be harder to kill if you're not running a slash/corrosive setup, but they shouldn't take much to kill & if they do, you're clearly building your weapon wrong.