Whilst I do not excuse the notion that the staff may have been vindictive (hiding behind the veil of RSA) let alone carrying poor service standards, what are the notional points of RSA?
Getting "RSA" wrong on either side of the scale can result in disastrous consequences for the staff. With a rise in alcohol related incidents on planes with very little reprimand of the perpetrators (but a very high criticism of the providers of alcohol involved), I would not be surprised if airlines were starting to get very edgy about alcohol. Even if it fits the "guidelines" (e.g. 1 standard drink per hour).
As someone in a service role, how do you make the call if someone has had too much or not, and then if they had had too much, how do you justify further when they show resistance (aggressive or otherwise)? The argument of "we served you more than 1 standard drink per hour" is not necessarily conducive to being sufficient proof.
Note that I am not implying that the OPs actually "had too much" or were aggressive, belligerent or otherwise offensive.
I would definitely lodge a complaint about the service standard, as that is independent of how much alcohol you had, or the RSA issue, and was present earlier than when the "RSA issue" had come to a head anyway.