People in hot arid deserts often look at the weather report and find out the RH is 20%. Then they say it's 20% in a warm tropical country, so we're in just as humid a place as that!
Doesn't a RH of 20% in air of 45 Celsius ambient hold way lesser water than 32 Celsius ambient air with a RH of 20%? Also, does altitude above sea level matter?
Technically, the dew point is the more appropriate indicator of comfort than the relative humidity (RH). I will use the example in the dew point link for illustration. You could live in an area with a temperature and dew point of 30 degrees, which would mean the air is at 100% RH. In contrast, it could be 80 degrees out with a dew point of 60 degrees for a RH of only 50% but this hotter day would feel much more humid and muggy. The higher the dew point relative to the temperature on a warm-to-hot day, the worse it will feel outside.
An example I like to give is to compare Minnesota to Maryland. The RH in northern Minnesota is often quite high in the summer, i.e., >80% (yearly average is ~70-75% https://www.forbes.com/sites/brianbrettschneider/2018/08/23/oh-the-humidity-why-is-alaska-the-most-humid-state/?sh=7bf40524330c). The dew point, however, is typically much lower relative to the temperature than in Maryland, so a typical 90 F day in July can feel way worse in Maryland than in Minnesota. The lower latitude also makes the sunlight more direct.
The answer to your question is definitely no on 2 accounts. First, what you call "less" depends on the purposes of your analysis (more on that in a sec). Second, a hotter air can hold more water before saturation, not the contrary.
Absolute humidity (AH) is defined as the mass of water per unit volume of air. Relative humidity (RH) is defined as the ratio of the current AH, to the saturation AH (which is the maximum absolute humidity the air can hold before it starts to condensate into droplets).
The saturation humidity increases with temperature. So, in a sense, you are right (if we invert your claim) in saying that at same RH but higher temperature, your AH will be higher (since $AH=RH*AH_{sat}(T)$). In this case, the warmer air will hold more mass of water per volume. However, in a meteorolgical context, it would likely not be pertinent to point that up. The relevant quantity here is indeed RH.
To illustrate, let's say it's hot outside. You're cooling yourself off by evaporating sweat off your skin. The rate at which you can evaporate it and thus chill will be limited by the humidity already present in the air, more precisely by the relative humidity. Since RH is a measure of how close you are to saturation, it is the one that is significant in telling you how much your evaporation rate will be lowered.
In short, when it comes to measuring human comfort in a meteorolgical condition, AH would be misleading while RH is pertinent IMO. I believe people are not committing a misconception, but instead using the appropriate tool when referring to RH to compare two climatic conditions.
