There are several grave environmental and civil problems with Starlink and other proposed massive constellations:

• The threat to the ozone layer (when these low-orbiting sats start re-entering en masse in the next few years, we’re going to have more aluminum in the upper atmosphere than ever before - a known problem)
• Overcrowding of LEO - the choicest orbital space over this planet is finite. Satellites in low orbit have tremendous kinetic energy and do not (cannot) fly in formation, as they spread out vertically; not that Starlink is designed to. Kessler Syndrome catastrophe or not, the risk of collisions is increasing rapidly. As some researchers have put it, LEO is the “Wild West” right now, and it definitely needs to be regulated by international treaty.
• Light and radio pollution - aside from exacerbating the accelerating ecological damage from light pollution, this extends even to orbiting assets like the Hubble Telescope, which is already seeing interference from Starlink sats. I don’t see why SpaceX or any corporation, let alone nation, deserves to monopolize any part of the global environment this way. Astronomy and upper atmosphere research don’t need to justify their existence, particularly not in this situation… and yes, stargazers on this planet deserve the right to a “clean” night sky.
• Corporate squatting - Starlink is approaching the point of outnumbering all other extant satellites from all other nations, since the start of the space age, combined. Why do they get to crowd everyone else out?
• Vulnerability to the space environment - when the Sun acts up, Starlink sats have been disabled before, and in numbers. This is a threat to satellites in general (obviously), many of which are not shielded properly, but launching bunches of these satellites at once increases the threat sharply. I’m sure you’d agree that orbital debris is not something we should take lightly.

I could go on, but I trust you get the point. I don’t object to temporary small-scale deployments of satellite groups during catastrophes, but we simply don’t need the permanent deployment of tens of thousands of satellites that the US, Europe and China intend to launch for global internet coverage - that can be almost entirely achieved from the ground.

Would this… proposed legislation… mean that SpaceX will now be prohibited from flooding LEO with Starlink comsats?

Loading the upper atmosphere with ozone-destroying aluminum and other heavy metals as those things fall out of orbit, not to mention rapidly increasing light and RF pollution, definitely qualify as an uncontrolled geoengineering experiment, albeit one whose effects were known before launch. I could go on about the deleterious effects of these orbiting swarms, but - the ball’s in your court, Congresswoman Greene.