Spectrum is a product of the Charter Communications company[0]. Further, it is very rare (possible non-existent) for 2 cable companies to operate in the same market. Time Warner Cable and Charter did not compete in any market, as far as I know, so it is unclear how their merger would create less competition when the cable industry mostly operates as a monopoly in any given market in the first place.
[0]https://en.wikipedia.org/wiki/Charter_Communications