As Cerberus wrote about 'U' English, replying to "How do you do" with "How do you do" used to be the case among some classes in England (at least), but it seems to be (sadly) nearly extinct. Kate Fox writes in the first chapter of Watching the English (which is about talking about the weather):
We used to have another option, at least for some social situations, but the ‘How do you do?’ greeting (to which the apparently ludicrous correct response is to repeat the question back ‘How do you do?’) is now regarded by many as somewhat archaic, and is no longer the universal standard greeting. The ‘Nice day, isn’t it?’ exchange must, however, be understood in the same light, and not taken literally: ‘How do you do?’ is not a real question about health or well-being, and ‘Nice day, isn’t it?’ is not a real question about the weather.
So in this usage, "How do you do?" wasn't an actual question about the person: it was just a meaningless greeting, and for instance what one might say when introduced to someone (in lieu of "Pleased to meet you"), presumably while tipping one's hat. In reply, the other person, also wishing to make the same meaningless greeting, would say "How do you do".
Note that "How do you do" in this usage was even spoken as a statement, not as a question (i.e., without a rising tone at the end).
These days "How do you do?" is more likely to be interpreted as an actual question. Interestingly, as n0nChun observes, one does sometimes hear a similar exchange these days, with "What's up" getting the reply "What's up", or even just "sup" — "sup".
The parsing of the as clause depends on intended usage; the as clause can modify the nearest substantive if used adjectivally, but can also modify the nearest verb (or other part of speech) if used adverbially.
Firstly, the function of the as clause must be evaluated. In this circumstance (and in similar usages), the multifaceted word as is applied as a preposition, in the sense of "in the capacity, character, condition, or role of". Therefore, its usage must be considered under the general properties of prepositional phrases.
A prepositional phrase can function either as an adverb or adjective, so an as clause can function identically. However, because the as clause acts as a modifier, the rules of modifier placement apply. Therefore, the position of the as clause may indicate which word it modifies, although this doesn't work in all contexts.
Here is an example of an as clause functioning adverbially (modifying the word discussed):
Because the KGB was monitoring them, they discussed the Party only as allowed by law.
Here is an example of an as clause functioning adjectivally (modifying the word party):
Wondering if the noise pollution would attract unwanted attention, they discussed their wild fraternity party as allowed by law.
If an adverbial as clause is intended, moving the clause closer to the verb (i.e., improving modifier placement) may eliminate ambiguity, as follows:
Exercising our right to free speech, we discussed, as allowed by law, whether the Supreme Court ruling was valid.
Clearly, as you illustrated with your "kitten" example, the parsing depends on context.
Addendum:
I have difficulty regarding the phrase as allowed by law as applying to both the noun socialism and the verb discussed. Being used adjunctively, I would assume it could only apply to one of the words.
You perhaps could construct the as clause as a disjunct, as follows:
As allowed by law, we discussed socialism.
In this construction, it would apply to the sentence as a whole. However, it would not apply specifically to both the verb discussed and the noun socialism. Additionally, in order to use the clause disjunctively, the as clause must be placed at the beginning or end of the sentence and be followed (or preceded) by a comma.
In sentences where the placement of an adjunctive as clause causes ambiguity (this can be considered a form of a misplaced modifier), the as clause can be interpreted as either modifying the verb or noun. When this ambiguity is intentionally employed to give a sentence a double meaning, it could even be considered a form of zeugma, a rhetorical device in which "a word modifies or governs two or more words so that it applies to each in a different sense".
Here is a general example of zeugma:
He fished for compliments and salmon.
Here is a subtle instance of zeugma with an as clause:
The prophecy was fulfilled as it was written.
The as clause appears as though it refers to two things simultaneously, because one cannot determine which word it actually modifies. This gives the sentence a double meaning. If we interpret the as clause as modifying prophecy, then the sentence means that the prophecy was fulfilled exactly as foretold. However, if we interpret it as modifying fulfilled, then the sentence means that the prophecy was being fulfilled while it was being written. By intentionally placing the modifier at an ambiguous position, I could employ zeugma. (The example was not as illustrative as I would prefer, but it was the only example that I could devise right now.)
Best Answer