High (comparative) weight + low reps builds strength (and muscle recruitment) without (necessarily) building lots of new muscle fibers. Muscle hypertrophy happens most often with lower weights and higher repetitions, plus loads of calories. A program like "Starting Strength" is not about hypertrophy.

Any exercise is potentially "unhealthy," particularly if it requires specialized movements. You can learn proper form for "base" lifts like the squat and deadlift without any equipment at first.