To be blunt, the whole 'Dark Elf magical information is wrong, and boobytrapped, and will 100% kill us instantly' is way way waaaay fucking overblown.
Let's start with the Waystone commands;
1. We're not entering direct code from Admin access - there's no risk of forgetting one curly bracket, resulting in the network exploding.
2. There are a limited amount of specific commands - we're not going to fumble the elvish for 'feed the baby' into 'defeat the baby', followed by all babies in range exploding, followed by ancient Elves going "Actually, why do we even have that button?"
3. The people who made the commands were competent, sane, and moral, with a justified assumption that no-one would subvert said codes in a way that required secret sabotage commands - so we may receive codes that don't do what we're told they do, but there's very little likelihood of a 'blow up Network' or 'subtly emit Dhar' command code existing.
4. There is an intelligent guiding consciousness in the Waystone Network - remember when we were giving the least-damaging commands of 'turning it on and off again', and after one or two tries said intelligence figured that we were just fucking around, and stopped accepting commands?
There are defences in place, to stop mere irritating use of codes, let alone harmful ones.
Next, the 'oh no, an apprentice of an apprentice of an apprentice of Spy-Satan from Backstabia, wasn't taught as well as she could be' issue.
Because that's what it is;
1. The Sorceress has not been (Physically, Mentally, Magically, etc) harmed by this misinformation - she did not explode upon using this technique. She's not going to explode from using it. It is not slowly poisoning her to death, it is not gradually reducing her Magic ability. It hasn't even reduced her theoretical and eventual maximum Magic score.
2. Receiving a technique considered sub-optimal by Spy-Satan is not a bad thing - sure, maybe the literal pinnacle of a Magic tradition has better ways of doing things, but do we? And sure, another lesser expert of literally multiple millennia in age considers it a waste of time in the long run, but our wizards are drastically unlikely to reach even a century, so does that negatively affect us?
3. We're not taking anything at face value - we're not going to regard what they give us as the One True Way that cannot be improved, and if it clashes with things we already know, then those things are automatically wrong. Cherry-picking useful flecks of gold from molten-hot magma is something we have experience in. And this time...
4. We have help - we have experts from multiple Magic traditions to check and improve on things, including said multiple millennia matrilinial-related mage engaged in a low-key shadow war with Morathi.
Sure, maybe that shadow war consists of the low-effort sending of relatively weak sorceress' and assassins every century or so, but it's still a question of "Are you cool enough to be related to me?" were 'no' means torturous death, and so far the answer has always been "Yes".
Also, what he said to the sorceress minion was basically "You're still using command codes? If you'd spent that time learning to actually code, maybe you could have been properly l33t, bitch."
A skillgate system is pretentious, sure, probably not the best most efficient idea, and in this case exists alongside systemic backstabbing evil, but its not the worst system.
Imagine if Dwarves did the same thing with runemasters, and gated knowledge behind skill and, I don't fucking know, koans. They'd have at least a 100 times as many at various levels of ability, instead of only teaching the literal 1% they think might eventually be capable of reaching the equivalent of Magic 10.