You do not specify any concrete line where you are immediately get worse as black, but still I probably can provide few ideas why that happens. I will cover the King's Indian (KI) but I hope that for Pirc it also works in some terms.
Indeed, in the King's Indian as black the price of every move is extremely high. With this you pay for the loss of control over the center and some development delay. Instead you get complex positions with much of hidden dynamic potential and almost all-the-game counterplay.
Unprepared White player can encounter unwanted fight for three results, which he is not ready for. There are a lot of examples (even at GM level) where evaluation is like +1.5 after the opening, but white doesn't know how to proceed and after several succecive mistakes he got much worse against experienced Black King's Indian player. Most victories for black in the KI are due to a deep understanding of the position, a great sense of dynamics and accumulated experience of black player. My GM coach always told me that if you play the Queen's Gambit with Black, you can easily combine it with the Slav Defense or Tarrasch. But if you play the King's Indian, then you should play only King's Indian. For the above reasons, it is so difficult to start successfully playing the KI with Black.
Based on the above, I can offer the following options for stop confusing in the King's Indian as a beginner:
- Do not be upset about lots of losses (seriously). In KI it is normal at the beginning of practice.
- Look for the counterplay during your play and analysis. Try not to memorize lines (there are too much of them!) but to estimate which way of counterplay will be most effective in current position (e.g. a6-b5 or e7-e5, advance King's side pawns or Queen's side). Remember, King's Indian guys often say that if you got the proper counterplay you are on the half way to win the game.
- Read and analyze classics. I suggest to start with "Zurich 1953" by David Bronstein and "I play against pieces" by Svetozar Gligoric. In 1950-s King's Indian began to rapidly evolve and in this books you can track a lot of common ideas. It is very instructive to see how black and white tried to improve their plans from game to game almost in one tournament! I also highly recommend the explanation of Gligoric how to deal with Saemisch as black.
- Play only King's Indian as black. Do not mix it with the other openings. In this case practice is extremely valuable.
- Set the time for playing KI (e.g. 3 months). If results after this period do not satisfy you, don't worry! Probably it is just "not your opening". Many chess enthusiasts all over the world are delighted with analysing sharp KI games, but how many of them use it in real over-the-board play?!