Only quote as much as is needed
As has always been our guidelines, we should only quote as much of the paid sourcebooks as is required to sufficiently support our answers. Sometimes a question requires entire paragraphs to include the appropriate context for the question, where possible we should reduce or remove unrelated or superfluous parts of the quoted material. Additionally, we should always be citing the source material.
Sometimes questions exist which can be answered solely by reproducing paid content. Let's imagine an example:
Question: "What is the stat-block for a Beholder?"
Clearly this question is going to invite answers that re-produce paid content for free.
Answer A: The Beholder is found in the Monster's Manual on page X
Answer B: Here's the Beholder statblock:
A good answer to that question would advise where the content can be found. A problematic answer would just reproduce the content verbatim.
The question we should consider when determining if content can/should be reproduced is "Does my quoted content remove the need to purchase the source material?" Looking back at our example if OP's goal was simply to obtain the paid content, answer B clearly removes the need to purchase they book, while answer A does not.
Let's compare your original answer with Thomas Markov's. While, by character count both answer's reproduce a similar amount of paid content from the DMG, only one actually reduces the need to purchase the sourcebook.
Thomas's answer quotes from the introduction of the chapter that explains what the rules cover and gives just enough of an example of what readers can expect from the materials so that they can judge whether they should purchase the material or not. It doesn't remove the need to purchase paid content to solve OP's actual problem however.
In simplified terms that answer says "The rules for this are in the DMG and here is an example of what you can expect from those rules". It gives OP all the information they need to solve their problem, and a good gauge on whether it is worth spending money for the answer they seek, without reproducing the part that makes purchasing the DMG unnecessary.
In contrast, your original answer reproduced the key table of content from the DMG (initially without attribution). While not exactly copy/paste, it had enough information in it that readers could easily get by with just that table rather than purchasing the DMG. This is why your answer got flagged and subsequently edited.
I feel your answer is no less complete with a redacted table. It's a good explanation of the process and provides enough of the table to give a good worked example. Including the full table only serves to reproduce content without actually adding to the answer.
A word on consistency
As you've discovered, copyright can get messy and generally we prefer not to get involved in it. However we also try to discourage use of pirated or otherwise illegally obtained material.
Do we always get the distinction right? Probably not. We aren't experts in this, but we follow the principles to the best of our ability. Sometimes this means a bit of inconsistency between different answers, but that is to be expected of a grey-area topic like copyright on SE.