A play on the term red pill as used to describe usually conservative-leaning people on the Internet who believe they (and only they) are able to see "the truth" about the world; particularly men who also fall into the spectrum of incel, MRA, and often times racist and/or nationalist groups. The term can also be used to describe most types of denizens of forums like 4chan and much of Reddit.
Soft Gel tablets are a type of pill that are designed to be easy to swallow and digest, and are described by Wikipedia as, "Consisting of a gelatin based shell surrounding a liquid fill." This is an adept analogy for the type of red pill philosophy exhibited by the groups mentioned above: easily repeated, easily understood rhetoric that seems logical, but breaks down upon outside scrutiny. (i.e.: easy to swallow, but dissolves easily.)
A softgel tried to bait me with a comment on Facebook by calling me an SJW for supporting equal pay, but I ignored him easily since he just spouted the same things you'd hear on 4chan.