Collecting depends on a variety of factors...
Is the native population healthy and thriving, with strong enough numbers that collection will not threaten the species?
Is the animal easily adapted to captivity, and able to survive under captive conditions without threat to health or safety?
Are you able to provide an optimal level of care for the animal?
Are you knowledgeable enough to provide excellent care for the animal, and able to provide vetrinary treatment in the case of an emergency?
Is it legal for you to collect a specimen from the wild?
If you can positively answer yes to all of the above questions, I see no problem with collecting a wild animal for captivity. HOWEVER...
If the animal does NOT adapt, does not eat, and does not THRIVE in captivity, it is your responsibility to ensure the animal is cared for in accordance with the law. Some states will not allow for a re-release of a wild animal once it is brought into captivity. You need to research this. In these states, an animal that is brought home as a captive, and which doesn't thrive, is condemned to suffer throughout it's painful captive existence or must be euthanized. Are you ready to accept that?
As long as the collection is legal, does not interfere with native populations, does not ensure death for the animal, and does not threaten or endanger native populations...I have no issue with collecting.
I currently have a wc Cal King, Sierra Garter, Rubber Boa, Rosy Boa and 1.1 Desert Banded Geckos. All are legally maintained and were legally collected from areas known to have thriving wild populations, and all are doing incredibl;y well as captive animals.
Honestly...you need to research the regulations and laws about the specific animals you intend to collect, as well as researching the health and viability of the local populations. Than you need to make the moral decision for yourself.
As for what herping "is"...it is finding and documenting wild reptile and amphibian species. It is NOT about collecting, it is NOT a hobby that supports commercial collection, and it is NOT a hobby that seeks to remove wild animals from wild populations. I found over 100 snakes last year, and I collected precisely 3 of them. I am the founder of the Eastern Sierra Herp Club, and one of our founding rules is that we do NOT collect during club-sponsored field trips. Herping is about finding and appreciating these wonderful animals. Collecting is a moral decision you need to make for yourself, once yuo have researched thoroughly the regulations and laws.
Another aspect to consider is this...In CA, where I live, the only way for me to legally own many species of snake is to colect them. Here, you cannot import, export, buy, sell, trade, or breed native reptile species without a permit. However, with the purchase of a fishing license, you can catch and keep a specified number of certain species. I have a Sierra Garter. The ONLY legal way for me to have that snake is to have caught it myself. So I did...
Good Luck!