The Mind Melter (and its Mind Mage counterpart in the fantasy game) are the most powerful psychics in the game, and they are so noted because they are powerful telepaths. In other media, the most obvious examples are Charles Xavier (X-Men) and Kimball Kinneson (Lensman). Other telepaths are not so potent, but often compensate with skill in application to make the most of more modest capability. In any event, telepaths (and similar sensitives) pose a challenge to any RIFTS campaign and this is a known issue with the game.
Playing a telepath means that your man possesses the power to violate the fundamental privacy of any individual entity, and likely the power to resist the same happening to your man. (Not assured, but you're a fool to not take some form of mind shielding if you can.) These powers, as usual, came in early- maybe even in utero. They're part of his perception of the environment around him, and as natural as his mundane senses (the "cocophony of voices" trope is bullshit; we easily learn to tune out background noise, which is what lots of people talking is, so telepaths will easily do the same with mental ones).
He'll reflexively use them by default, regardless of Alignment, and exploit the benefits gained by doing so: appear to be a genius, always able to manipulate social environments with ease, glad-hand anyone not psychic (or a savvy magic-user) with aplomb, and know what to do/say before it's needed. The first time he runs into someone able to block him, it'll be a defining moment in his life and you should note what that moment was (if it's happened before play begins; not guaranteed for the top-tier talents). Because there is no obvious power display for telepathy, telepaths can exist quietly within a community for years- even their entire lives. Their powers allow those with even a modicum of ambition to easily move into whatever position they desire, so long as there is nothing to oppose their doing so. Therefore, the Coalition propaganda against psychics is readily justified; it's also why the Inner Elite are where they are- that's how they got there.
What does this mean? It means that keeping information away from a telepath is nigh-impossible. The powerful ones can rummage through the minds of mundanes at range, with no obvious display of power, and acquire whatever information that they desire while the weaker ones incorporate varying degrees of mundane scamming skills to fill the gap; want passwords, blackmail material, confirmation of your suspicions, etc. well it's easy (if not trivial) to get it as a telepath. GMs need to work with this reality; the Coalition does it with a combination of very strict information control and active searching for unauthorized telepaths (i.e. not the Inner Elite or their approved lapdogs), Psyscape with a culture of shielding minds by default, and so on- with those that cannot or will not taking measures to protect themselves being easy prey for telepathic intrusion. (So most folks are helpless, and only proper nescience or ignorance will save them.)
It's hard to be a Xavier or Kinneson; you really do need to hone your discipline and carefully act upon what you learn. Being a more selfish or evil character is so much easier, but even good telepaths tend towards paternalism with regard to non-psychics; their powers are the norm of their frame of reference, so lacking the ability seems like being infantilized to a certain degree and the good ones act accordingly.