The terms patriarchy (or rather "patriarch" and all variations of the word), and toxic masculinity don't have negative implications because they aren't entirely new words to the layperson; they're words that have a meaning to them already, and are complemented by terms that illustrate the opposite as well. Even if Patriarchy doesn't mean to them "system with inherent biases, and embedded prejudices with males at its head, that prevent females or other disenfranchised groups from getting ahead as well through equal opportunity ", patriarch(y) still has the term matriarch as its buffer. Likewise toxic Masculinity has the term toxic used as a buffer as well, making the difference clear. But mansplaining is different because it has no embedded neutral meaning to modify, or feminine complementary term to offset it. It's just "condescending explanation by a man, usually to woman", and that's all it means. And it becomes condescending in and of itself because it becomes part of the laypersons dialogue as is. Leading to situations where simply explaining as a male to female gets written off; either to his face, or later through their conversations, as "guy x mansplaining again".