When writing about other people's opinions in an essay, the use of quotation marks depends on the specific situation and cannot be generalized to say that they are used or not used.
There are three cases to illustrate this-
First: using colons and quotation marksIf the ideas used in the text have a source and are written in word for word, then it is a direct quote and requires colons and quotation marks. For example:
1. When talking about the issue of humility and pride, I am reminded of what a great man once said, "Humility makes one progress, pride makes one fall behind."
2. Whether the roadside stalls should be abolished or not, the residents of the neighborhood debated. Zhang Dajie said, "Roadside stalls should be allowed, so that it can be convenient for the masses to buy things." And Li Dajie was opposed to the idea, saying, "Roadside stalls affect traffic."
Second: Use only quotation marks, not colonsIf you show someone else's point of view by not quoting all of it, but only the key elements of it, you can incorporate someone else's point of view into a sentence without using a colon, just quotation marks. For example--
As for whether square dancing should be practiced in small districts, it is clear that there are two opposing views, and Auntie Wang clearly stated that "square dancing can be practiced in small districts", and her reasoning is that it is "good for the elderly's Physical health. But Zhang is against it, saying "the sound is too loud to disturb the people".
The third kind: without quotation marksIf the point of view expressed is not a direct quotation of the original words, but a quotation of the general idea, then there is no need for quotation marks, nor do you need to use a colon, with a comma to quote can be. For example -
Practice makes perfect, as a great man said, to know what a pear tastes like, then you have to taste it yourself.
On the subject of what punctuation to use for quotations, it's probably the three cases above.