Lozano's is an excellent paper. Take into account it is not intended to upper-intermediate students or advanced students. In my opinion that paper is great for educated native speakers and for non-native highly skilled Spanish teachers, but everyone can get something from it, at least, a deep reflexion about what has been learned so far.
As a native speaker, I always find very strange those assertions about subjunctive being related with "doubt, anticipation or emotion" or the like. Sometimes I found that even disturbing.
You said "This seems to me to be contrary to the basic function of the subjective."(I suppose you mean "subjunctive") so you might need to review your idea about Spanish subjunctive.
The example you quoted is very important as it is one of not many cases without a default case. I mean, some cases are very strong:
No creo que venga (subjunctive by default as it speaks of the absence of a specific notion -él viene- within the mind of the speaker)
No creo que viene (a very very infrequent case used solely to deny something that has been stated as true within the group of reference: "everybody is saying 'he comes! he comes!' but I won't bite that bait" )
Quizás venga (subjunctive by default as 'el viene' is just one of many options, not an option we focus on)
Quizás viene (indicative 'liven it up' and now it becomes something more indicating that outcome as having more relevance that other outcomes, for instance -but not restricted to-, because the action is more likely than other actions)
Busco una persona que hable español (subjunctive -not so much by default- because "que hable español" is just an adjective. I'm not looking for some specific person but someone who fits that description)
Busco una persona que habla español (indicative 'liven it up' pointing to some specific person even in the case I don't know who that person is and I am just taking as true that a real person fitting that description really exists)
and then we reach the example taken from Lozano
Lo bueno es que no tenemos que estudiar en verano (the "thing" -no tenemos que estudiar en verano- is presented as a lively action, so it equals to "No tenemos que estudiar en verano y eso es bueno", that is, a declaration that introduces new information or reminds or insists on it)
Lo bueno es que no tengamos que estudiar en verano (the "thing" -no tenemos que estudiar en verano- is presented as a suffocated action, so the comment is aim to present an opinion about the "thing". When you talk to somebody is not logical to say "I like xtrmksts!" because the person who hears it would be unable to represent your likings if he or she can't make a conceptual image of a "xtrmksts", so "xtrmksts" is supposed a shared concept. Well, subjunctive has completely "thingified" the action as it is a shared notion. As a final check, you can't present new information with subjunctive "No tengamos
que estudiar en verano y eso es bueno", "Que no tengamos que estudiar en verano y
eso es bueno", "Que no tengamos que estudiar en verano es bueno"
-"Lo bueno es que no tengamos que estudiar en verano" but more difficult to parse)
Lo bueno es no tener que estudiar en verano (there's no mood here -and there's no "que" as "no tener que estudiar en verano" is a thing by definition. As it has no subject, it's a general idea or prescription).
Well, I hope this helps. You're welcome to ask in this site every question you have in this and other subjects. Don't be afraid of making your own sentences and ask about them.