Today I saw someone on the blockchain bragging about "catching arbitrage opportunities" again.

My first reaction wasn't envy, but rather thinking: Are you really making money, or are you paying fees to others (or robots)...
Sandwich attacks, to put it simply, are like waiting in line to buy bubble tea, with two people on either side trapping you in the middle. When the price rises, you might think you're just slow on the draw.
Though I panic in my words, I still follow the usual process: first check the few transactions before and after, slippage settings, and the traces of repeated transactions from the same address in the block, to confirm I wasn't fed false information.
Recently, the privacy coins/mixing services have been noisy about compliance, to the point of breaking out.
I think it's the same story: you think it's about freedom/opportunity, but others might only see a gray area that can be exploited.
Anyway, I now prefer to do fewer trades rather than become a "leek tax" contributor—it's ridiculous.