Scorpion,
There are "giants" today, too -- they're ordinary people with an excess of growth hormone. But even if our ancestors were taller, that still wouldn't prove we "degraded." Evolution does not imply "getting bigger and stronger and brainier and healthier." It is simply a matter of adapting to environmental pressure -- which could mean getting smaller and quicker as easily as bigger and stronger. You'll notice a certain lack of big, strong dinosaurs roaming the earth.
How much reading did you do on evolutionary theory and the evidence for it, before reaching your conclusions?