The EM Spectrum started as just two options, like a diamond ring with each half of the ring a different colour (frequency). It was from these two options that the cosmos developed, simply expanding and growing into more and more contexts.
Expressed in binary/digital terms, the highest possible frequency/speed is when both '-1' and '+1' are occuring simultaneously. The lowest possible frequency/speed is when neither '-1' or '+1' are being touched. The sum total of both of these values is '0', i.e. the same. Thus the beginning and end of the EM spectrum are the same place.