Swing points are the only objective marks on a chart
A swing high is a candle whose high exceeds the candles on both sides. A swing low is the reverse. That is the whole definition, and its value is that it does not depend on your opinion.
Two traders can disagree about whether a trend "feels" strong. They cannot disagree about whether 3,381 is lower than 3,340.
The strictness problem
Every wiggle technically qualifies. On a 5-minute chart you would mark hundreds, and marking everything is the same as marking nothing.
The practical fix is a lookback: require the high to exceed the highs of the two or three candles on each side. Three either side gives roughly a dozen meaningful swings on a typical 4-hour chart — enough to read structure, few enough to see it.
Whatever you choose, apply it consistently. Loosening the definition to find a swing that supports your view is how objective analysis becomes confirmation.