The second example should actually be
class C {
void mightFail() { ... }
~C() { doCleanup(); }
};
C c;
c.mightFail();
Anyway, I hate this slide deck so much.
1. The author's point could be made in far fewer slides. As in, like, two slides. I hate presentations that are disrespectful of the audience's time for the sake of being cute.
2. I am generally unimpressed by arguments of the form:
(a) Language X has flaw Y.
(b) Therefore language X is unsuitable for development.
This can be instantiated for every language X for some flaw Y and is not an argument against any language. You need to additionally make the argument:
(c) Y is so serious that it outweighs the considerations in favor of X and against the other languages one might reasonably use.
Of course (c) is an incredibly high bar, which is why most anti-language zealot arguments do not even attempt to make it, and also why most anti-language zealotry is silly.
In order to do (c) in this case, you would have to make the case that writing finally clauses is worse overall than, e.g. debugging memory corruption errors, and writing copy constructors and overloaded assignment operators, and all the other baggage of C++, rather than handwaving them away with "the downsides have been exaggerated".
Which, by the way, is ironically the biggest flaw of this slide deck: the author vastly exaggerates the downsides of finally. try/finally is no worse than checking the result codes of C syscalls, and it is sometimes better. I don't recall the C style of programming stopping Ken Thompson from building great things and I doubt that try/finally is actually what stops Java programmers from building great things.