That's not my experience, having played numerous competitive games. Bhopping in CS, wavedashing in melee, all of the various glitches necessary when speedrunning almost any game, are pretty universally loved and players that can perform them well are looked up to.
1) How do you know it's a loophole. Sure, there's probably some instances where it's pretty obvious what you're doing is a loophole. But others require you to be up-to-date on economic and political debates as well as being extremely well read in the tax law. Similarly, half of the people who signed the loophole into law may consider it not a loophole and the other half might consider it to be a loophole. In general there's no way to know.
2) What if part of the tax law was signed into law specifically as a favor to a corporate entity who funded a political candidate, but disguised with complicated language so it's not obvious who is getting the favor. In this instance realizing that you qualify for the tax reduction would be considered a loophole by the shady politician that created the law ... or a bonus because it will obfuscate who the kickback is going to.
In case 1), I feel a little bit uncomfortable with calling someone's action unethical when it depends on their ability to understand a complicated law AND the economic scenario and theory behind the law AND the minds of ALL politicians involved with making the law.
In case 2), I actively want everyone to abuse loopholes created for this purpose as much as possible. It's like watching someone burn themselves on a stove. If a politician is doing this sort of thing, I want it to blow up in their face so they learn not to try to do such things in the future.
I don't know if it's that simple. If we define a loophole as a tax exemption that was not intended to be used in a certain way by the lawmakers, then I don't think it's fair to call something a loophole if it has been widely known about and used for many years. It's on the lawmakers to clarify their intentions with new laws. That's literally their only job.
But what counts as a loophole? There's a law that says you can deduct your interest income, so is doing that "using a loophole?" If that doesn't count as a loophole, then why does the double Irish arrangement count as a loophole? They are both just taking advantage of a law.
The obvious response to this dilemma is to bring up what lawmakers intended. That makes sense. But why not just have the lawmakers themselves clarify their intentions by closing things they consider to be loopholes? It seems unreasonable to expect each company to guess the intentions of each tax law.
Devil is in the details.
Imagine it is you or your business, looking at a situation where a loophole will give you a truly consequential big tax savings, maybe 30% of the annual top line income (for you, your company, etc.). It is perfectly legal. What do you do?
OK, now your company is involved in something that promotes general good, social welfare, clean energy, etc. You are at the edge of survival, and using this legal loophole will make the difference keeping you alive for the next year, and actually help poor people or endangered species?
Or, you are merely in the finance division of an ordinary company, with a responsibility to deliver maximum shareholder value and maximum profits to go to employee bonuses, and your job depends on properly and legally maximizing income and avoiding taxes?
While it's easy to proclaim from on high "do what was intended", the actual situation is quite different.
The only solution is better laws, without the bugs, or laws written for situations (such as transaction taxes) that aren't so bug-prone.
Comparisons are stupid but still:
Compare loopholes with game glitches. They are not intended, they break the system and every player is hated for using them.
Often "pro-loopholers" claim that everyone tries to optimize their tax, so why not big companies. But tax breaks which are used by the regular guy have clear implications: Support families, incentivize businesses, steer society in a certain direction. Loopholes are just edge cases that have not been thought of, thus have to be closed as soon as possible. They are the glitch in a perfect tax law. Don't exploit them!