While beginners sometimes confuse these terms with standard multi-partnered polyamory, these are actually major relationship red flags that breed huge power imbalances. They are deeply criticized, and high unethical dating behaviors.
Collecting - Hoarding Beyond Capacity
A collector is an individual who compulsively adds romantic or sexual partners well beyond their psychological, emotional, or logistically capacity to fulfill them.
Collectors treat people as possessions, trophies, or personal achievements rather than human beings. They collect connections to soothe their own internal insecurities, build their ego, or boast to outsiders about how desired they are.
Collectors completely ignore the boundaries of natural polysaturation points. They continuously introduce new partners to their polyamory group, which makes existing partners feeling emotional neglect, and that they are reduce to "collateral damage" as they survive on emotional scraps form the collector.
Harems - Closed Loop Power
A harem structure occurs when a central individual dates multiple partners who are required to remain strictly monogamous and faithful to that one central individual, while the individual retains the freedom to date whoever they want. We see this structure practiced throughout history, as well as in modern "smut" literature (though sometimes incorrectly labeled).
Unlike ethical polyamory where each partner is treated equally and has freedoms to choose pursuing other connections, a harem is designed with a lopsided power structure. The central individual controls the sexual and romantic landscape of the entire group.
Harems are often disguised as a "medical safety" measure, with the idea that partners cannot date others in order to prevent STI transmission. However, this reasoning has a hypocritical double standard as the central person is free to have intercourse with whoever they want. This double standard masks the deep-seated need for control and lack of trust in partner's personal autonomy.