Critical Reasoning

I have always thought and I believe it's written in all the books that
you cannot:

1) bring outside knowledge into your reasoning
2) make up facts that are not explicitly stated in the stimulus or
that could not be logically derived from the stimulus

In other words, you must take for the fact that what is stated in the
stimulus is true (even if black is said to be white). You cannot question premises presented in the stimulus.

(Note: I am not talking about specific situations when new facts can come in
the problem space from answer choices in certain question types such
as strengthen, weaken, resolve the paradox etc.)

Yet, there are two questions (both from the OG) that in my opinion either contradict this, or I must be missing something.

Theater Critic: The play La Finestrina, now at Central Theater, was written in Italy in the eighteenth century. The director claims that this production is as similar to the original production as is possible in a modern theater. Although the actor who plays Harlequin the clown gives a performance very reminiscent of the twentieth-century American comedian Groucho Marx, Marx's comic style was very much within the comic acting tradition that had begun in sixteenth-century Italy.

The considerations given best serve as part of an argument that

(A) modern audiences would find it hard to tolerate certain characteristics of a historically accurate performance of an eighteenth-century play
(B) Groucho Marx once performed the part of the character Harlequin in La Finestrina
(C) in the United States the training of actors in the twentieth century is based on principles that do not differ radically from those that underlay the training of actors in eighteenth-century Italy
(D) the performance of the actor who plays Harlequin in La Finestrina does not serve as evidence against the director's claim
(E) the director of La Finestrina must have advised the actor who plays Harlequin to model his performance on comic performances of Groucho Marx

The OA is [spoiler](D)[/spoiler].

https://www.beatthegmat.com/what-is-mean ... tml#447423

Here are my objections:

a) How do you know that 16th century comic style was still available in the 18 century? For all we know, it could have been quite the opposite. Who knows?

b) Assuming that the 16th century comic style was available in the 18th century, how can we extrapolate from it to claim that this was an accurate characteristic of the comic style that was actually used in the 18th century?

IMO, for (D) to be a logical answer (i.e., answer that would flow from the stimulus), I would have to know that the 16th century style was not only available in the 18th century, but actually practiced. Otherwise, if that style was available but absolutely not used, how can we claim that the production was close to the original? If it were close to the original, it would use the comic style that had been actually used in the 18th century.

Here's the second problem:

In the past, most children who went sledding in the winter snow in Verland used wooden sleds with runners and steering bars. Ten years ago, smooth plastic sleds became popular; they go faster than wooden sleds but are harder to steer and slow. The concern that plastic sleds are more dangerous is clearly borne out by the fact that the number of children injured while sledding was much higher last winter than it was ten years ago.

Which of the following, if true in Verland, most seriously undermines the force of the evidence cited?

A. A few children still use traditional wooden sleds.
B. Very few children wear any kind of protective gear, such as helmets, while sledding.
C. Plastic sleds can be used in a much wider variety of snow conditions than wooden sleds can.
D. Most sledding injuries occur when a sled collides with a tree, a rock, or another sled.
E. Because the traditional wooden sled can carry more than one rider, an accident involving a wooden sled can result in several children being injured.

The OA is C.

https://www.beatthegmat.com/plastic-sleds-t30275.html

I thought that this answer choice cannot be correct because I thought that since plastic sleds can be used in much wider variety of snow conditions, they are potentially more dangerous than wooden sleds. For example, if plastic sleds can be used on icy snow and wooden cannot, they must be more dangerous.

Here's what Ron said to my objection:

You just made up the idea of "more dangerous conditions" at random. you can't just make up facts at random and then use them in an argument!
you are assuming (for no particular reason) that the additional varieties of snow are more dangerous; you could just as well assume that they are less dangerous.

So what I don't understand is that how come that in the first problem we are not making facts by assuming that the style that had begun in the 16th century was still used in the 18th century, and in the second example I am making facts by assuming that wider variety of snow conditions are more dangerous?

I would be very grateful if you could point to a logical mistake in my reasoning, and not to discuss how we can arrive at the correct answer in those questions and why other answer choices are wrong.

I would really appreciate if all our CR experts can weigh in with their insight.

Thanks in advance.