While previous answers/comments are correct in that "stuff" takes the singular form of a verb, I think they are missing the point.
The verb in this case is "should" which is the same in plural and singular anyway, so the question of grammaticality here isn't about the verb.
Where the potential singular/plural clash comes in with this sentence is in the fact that you have "stuff" (which the OP is mistaking for a plural), being compared to the singular
So, first off "stuff" isn't plural, so there's no problem.
Second, I'm not sure that there'd be a problem even if "stuff" were plural.
cf "Eight snakes shouldn't feel like an octopus"
In that sentence it looks like maybe it's ok because it's a simile.
But then in "Hurricanes are a threat to the infrastructure" you've got
a plural BEING a singular.
So yes, it's grammatical. But the "stuff takes a singular verb" point, while true, is not relevant.