I'm not sure that entirely explains the reputation Babylon's first season seems to have online, though.

As an example, TNG is almost entirely episodic and made in the same era, yet it's generally regarded well. The first season there is also known to be bad, but more so because it's actually poorly implemented until they discovered what works in season 2, which is still episodic.

The same for DS9, which has a poor season 1 that has to be pushed through as they find their feet. That too remains mostly episodic until the later seasons with the dominion war, yet I haven't seen the same suggestions for watch guides to skip most of the early seasons to get to the serialized stuff, people usually still consider the good episodic standalones of DS9 to be worth watching, from what I can tell.

There's something oddly unique about the Babylon 5 community suggesting watch lists to avoid any episodic content from the first season specifically, despite the show starting out on way stronger footing than either DS9 or TNG. At least for me, it gave a perception that the first season is nigh unwatchable dreck that most only tolerate once for the setup it provides, emphasizing to grind through it for the pay off.

But my actual experience with it makes the near universal dislike of it's season 1 bewildering, especially as they are not entirely episodic in the sense that virtually all of them so far have seemingly contributed toward the bigger arc in some way, even the monster of the week episodes.