First thing, I like the false comparisons. They really add to your point. It also goes to drive home that point you made in the second sentence, you know, a little research.

Now, hydraulic fracturing may be primitive sounding. But compared to what? Most modern oil and gas recovery is startlingly similar. Drilling muds frequently cause some hydraulic fracture because you cannot balance all borehole pressures along the entire length of a borehole simultaneously with a single drilling mud weight. Granted these muds contain a different set of chemicals than what is used for purposefully fracturing horizontal wells.

Which brings up another point which even a 'little' research should have lead you to realize. The depths where these wells are drilled are well below drinking water aquifers. In fact, all pore fluids at these depths are quite concentrated brines. You're looking at 1 km + below ground surface. There is a density barrier between these brines and the fresh, drinking water aquifers which we frequently use for tap water and farming. At the flow rates you are dealing with (cm/day to cm/year) no mixing can really take place due to the extremely low Reynold's numbers. I won't say that contamination cannot migrate, since I cannot know that, only that it is exceedingly unlikely.

Furthermore, if fluids could flow freely in these formations, would we need to fracture them at all? The answer is obviously no. That would be what is known as a conventional reservoir. Hydraulic fracturing generally takes place in gas shales. These have hydraulic conductivities on the order of 10^-12 cm/s. Unless the fracture reaches a more conductive body, that fluid isn't going anywhere.

Would the fluid reach a more conductive body? Its possible. It would be undesirable, since you would lose any production from that particular well. Chances are any loses would be trapped by a different aquitard (a layer with very low hydraulic conductivity). Hydraulic fractures tend to deflect when they reach such a phase interface, though. The stresses tend to not be the same on both sides of the interface. A useful analogy would be activation energy in chemistry.

The gas itself is methane. Methane is produced in the subsurface naturally (which is why its called natural gas). It is concievable that greater amounts might be present in the subsurface due to hydraulic fracturing of gas shales, but this would be undesirable for everyone involved since that gas would be lost from production. Which isn't to say that leaks cannot happen, but I am aware of no such cases (and yes, I looked, this is my area of study).

As for earthquakes, you have to first understand what causes earthquakes. Earthquakes are caused when the crust of the earth yields. This means that the stresses become greater than the rock's ability to withstand them. Hydraulic fracture also yields rock. There was research done in California to determine if such yielding could be used to control stresses on the San Andreas fault. It came to nothing because, presently, we are not able to drill deep enough and pump enough fluid to reduce effective stresses to sufficient levels to induce controlled yield. Furthermore, any deep mining city experiences rock bursts. These are also caused when stresses in the rock lead to yield. These feel like small earthquakes, and are picked up on seismographs just like earthquakes, but they cause no damage.

I do believe we need to better understand what goes on during hydraulic fracture. It is exceedingly complex. It is not, however, akin to fishing with dynamite. Open pit mining may be a fair comparison to that, although even there your analogy falls short. I am glad you have an interest in this field, however. It is an important one with a lot of potential. Further study on your part may not change your mind, but will help you make sounder arguments.

Good Luck