I haven't really attempted to analyse the usage of -ee as a noun formant, but looking at these two it seems to be that thematic relations are trumping syntactic considerations like transitivity.
"Standing" is not a particularly active activity. In some languages, the corresponding verbal expression is formally stative (e.g. French être debout lit. "be upright") or at least more stative than other intransitives (e.g. German ist gestanden "stood" vs. hat sich gelehnt "leaned"). So a standing person is kind of on the borderline between agent (someone who performs an action) and experiencer (someone who receives a sensation).
-er is a prototypical an agent suffix whereas -ee is primarily associated with patients and experiencers. So the less "agent-like" the agent, the more likely the use of a prototypically patient suffix. You can get some idea of how active certain verbs are perceived to be by noting what sorts of constructions they generally appear in. If you are in work, you are described as "working" and what you are is a "worker". But if you have gone into retirement, you are described as "retired" and what you are is a "retiree". Similarly, someone who devotes themselves to a guru is described as "devoted", not "devoting" and, consequently, a "devotee", not a *devoter.
"Stand" is in a more nebulous area than either of these two examples, so it's not surprising we have variation on the order of "standee" vs. "bystander". "Decide" isn't, since the idea of volition (a primary characteristic of the prototypical agent) is so central. This is why *decidee doesn't work.
(I'm trying to test this working hypothesis with other weakly active intransitive verbs and having trouble coming up with candidates. Any suggestions?)
no subject
"Standing" is not a particularly active activity. In some languages, the corresponding verbal expression is formally stative (e.g. French être debout lit. "be upright") or at least more stative than other intransitives (e.g. German ist gestanden "stood" vs. hat sich gelehnt "leaned"). So a standing person is kind of on the borderline between agent (someone who performs an action) and experiencer (someone who receives a sensation).
-er is a prototypical an agent suffix whereas -ee is primarily associated with patients and experiencers. So the less "agent-like" the agent, the more likely the use of a prototypically patient suffix. You can get some idea of how active certain verbs are perceived to be by noting what sorts of constructions they generally appear in. If you are in work, you are described as "working" and what you are is a "worker". But if you have gone into retirement, you are described as "retired" and what you are is a "retiree". Similarly, someone who devotes themselves to a guru is described as "devoted", not "devoting" and, consequently, a "devotee", not a *devoter.
"Stand" is in a more nebulous area than either of these two examples, so it's not surprising we have variation on the order of "standee" vs. "bystander". "Decide" isn't, since the idea of volition (a primary characteristic of the prototypical agent) is so central. This is why *decidee doesn't work.
(I'm trying to test this working hypothesis with other weakly active intransitive verbs and having trouble coming up with candidates. Any suggestions?)