There is a well-known mashal that should be helpful in the struggle for shmiras einayim.
It is the late 1800’s and an ignorant farmer is tilling his field when he comes upon some unknown substance. He has it tested and it turns out to be a precious metal. Prospectors hear about his find and offer him a handsome sum for his tract of land, but he hangs on and waits as the competition grows and their offers increase. Finally, he decides to sell his field to a wealthy financier who lives in the big city. The fellow sends him a nice advance payment and asks him to meet him at his office where they will close the deal. The farmer agrees to make the trip, but the big city is far away, about a two-week trip from his village if he travels by horse. His more sophisticated neighbors, however, catch him up with the times, telling him about the new mode of transportation, the train.
Thrilled, he goes to the central train station to purchase a ticket. The lady behind the ticket counter asks him what type of ticket he wishes to purchase, which throws him for a loop. She explains that one can travel either first, second, or third class.
“Third-class tickets guarantees a place on the train but nothing more. There may be a seat on a hard bench, but not necessarily; you may have stand for the entire trip. First come, first serve. Second class guarantees a seat, but costs somewhat more.”
Giving him a quick once over, she figures that there is no point describing first class, but indignantly he insists. Rolling her eyes, she explains the luxuries and amenities offered to the first-class passengers, which guarantee them a very comfortable journey. She concludes, “It’s generally only for the very, very wealthy.”
Sensing her condescension, he juts out his chin and tells her, “First class for me,” and pays the exorbitant price.
The train was scheduled to depart in several days, and the farmer noted the date and time.
Departure day arrives and the farmer is so excited that he arrives at the station two hours early. Somewhat confused by the process, however, and too proud to ask, he decides to go with the flow, and just copy whatever the other passengers are doing. The train pulls into the station and since it is still early, most of the passengers have not yet arrived. He notices, however, some passengers boarding the very last car on the train, so he follows them in. He observes them looking around furtively and then squeezing beneath the benches, so of course he does the same. Somewhat put off by the lack of luxury but pleased with the warm air flowing from a nearby vent, he gets into a cozy position and in no time falls asleep.
The next thing he knows he is being awoken by a furious man who is kicking him and pulling him out from under the bench. Startled and disoriented, he stumbles to his feet and confronts his attacker. “Who are you?!”
The man smirks, grabs his shirt, and speaks right into his face. “I am the conductor. That’s who. And you lowlife are trying to hitch a free ride.”
“No I’m not! I paid top dollar for a first-class seat,” he responds, which elicits peals of laughter from the other passengers, who are relishing the free entertainment. He starts fishing around and to their utter surprise pulls out, just as he said, a first-class ticket!
The conductor studies the ticket, realizes that it is authentic, and then, speaking in the respectfully hushed tones reserved for the very wealthy, asks the farmer:
“Sir. You have a first-class ticket. Why were you under the bench?”
The farmer’s face flushes in embarrassment, “But that’s what everybody else was doing” ... to which the conductor tells him:
“Sir. You are not everybody else.”
Klal Yisrael is the Chosen Nation. Since Mattan Torah we are elevated.
Princely.
If you see a cat rummaging through your garbage and finding what for it is a delicacy - say, a discarded chicken bone, would you feels pangs of jealousy? Will you feel deprived of the pleasure of eating that bone? Of course not. It is nothing more than garbage.
The same is true for tumah. It’s just not our thing. The world out there may have completely lost their sense of kedushah, but we are not them. Es past mir nisht, it is unbecoming for me. Our sense of pride should prevent us from sullying ourselves with tumah.