The real reason for this is the demographics--In general, people who play as heavy (not all, but most nowadays) are new players, who have a much lesser grasp of the in game mechanics or map features, or the way that CQC works, etc.

On the opposite end of the spectrum we have scouts--most of the scouts who are complaining about ridiculous heavy spam are among what I lovingly call the "OG Cult". We have been around for a very long time, and I can't speak for all, but most of us went through the days of Slayer Logi permascan AR 514 with our shoulders high, and our profiles low, proud to be some of the few who actually ran scouts since day 1. These are the players who know the maps, understand the mechanics, and have become powerful while their suit was in a bad place.

The heavy and the scout each attract their own types of players, however, the ones that are more liable to complain are the newer players, the ones that don't understand the mechanics or how they work, and by coincidence, these player's demographic is comprised mainly of heavies.

These new players seem to have some ingrained sense of entitltement to fair 1v1 fights where even a militia heavy straight from the academy could slaughter even the game's toughest scouts. The problem is, the inherent play style that the scout utilizes requires trickery, a basic knowledge of human psychology, and an deep in depth knowledge of in-game mechanics.

Most players find this unfair, and believe that by donning the all-mighty sentinel suit that they should somehow become invulnerable, and that things such as the use of tactics or even their personal gun game are useless in comparison to the incredible advantages given to them by donning said sentinel suit.

When they are killed by something that is smaller and faster than them, it seems like a spit in the face, and indeed, for many, it is. They know that their skill and knowledge of game mechanics was less than that of their opponents, yet refuse to admit it. Instead, they become bitter and frustrated as they know that their gear is inherently stronger, yet they cannot beat their opponents.

To this, I have to say--Suck it the **** up. Seriously. 6/10 of the scouts complaining have been scouts throughout the dark ages, where the supremacy of fine rifles and brick tanked logis with perma-scans reigned supreme, and many of us even thrived (to whatever extent we were allowed).

You HMG sentinels have been given superior weaponry and suits, yet refuse to adapt to a battlefield in which tactical decisions and gun-game matter.


Despite saying this, however--
Are scouts OP? Yes. Will Charlie fix that? Yes, for the most part. Some may need buffs post Charlie, others, nerfs.

And we do openly admit it. We understand the game mechanics and the reasons why certain scouts coughCaldaricough are OP.

--BUT!--

Are Sentinels OP? Yes. Will Charlie fix that? No, all it will do is make it so that core skills will need to be close to maxed or maxed to fit full proto.

However, the lack of acknowledgement of the issues making the sentinel OP as well as the condescending, brash, rude, degenerate, and occasionally illiterate ways that the Sentinel community represent themselves makes the glaring balance problems all the more annoying for many of us long-timers.

TL;DR-- The reason Sentinels complain so much about scouts is because they are generally newer players, and the very way the sentinel role works causes them to resent scouts in particular.