If there is no plan to actually start discussing politics more, sentences like "Could we talk about something closer to Easy Mode, so we can level up together?" take on an air of "I think you're failing at politics, and also I'm going to lie to you."

I'm not sure I understand the scenario you have in mind, but I'll reply and you can elaborate if I seem to be missing your point.

It might come off as beating-around-the-bush, yes, if you talk too indirectly and rely too much on metaphor. In my experience, LWers generally err in the opposite direction, of phrasing things too harshly and pejoratively, so I'm more interested in brainstorming strategies for mitigating our negativity than brainstorming strategies for mitigating our self-censorship.

Both are important, but I'm not sure how to teach any techniques that require moderation and context-sensitivity if it can always be objected that they can be overused, or used unskillfully. Maybe the solution is to look at specific examples of conversations and ask what the best move would have been at various junctures, so we can talk in more concrete detail.

if we start doing this consistency will pressure us to discuss partisan politics more.

Why? Because we talk about apolitical things that are also 'hard'?

"discussing politics is usually a bad use of my time, even though arguing with strangers online appeals to my tribal instincts."

When in doubt, yes, use complete sentences. But neutral language is harder than most people think, and if your audience doesn't associate a super positive affect with you, 'neutral' assertions can come across as very negative (especially online). E.g., for the specific example you gave: a not-especially-disposed-to-be-sympathetic reader who likes politics can take you to be implying some combination of 'politics is a waste of time,' 'your time is less valuable than mine (hence it matters less if you waste yours on politics),' 'you're being tribalistic (biased, savage, irrational...)', and 'you're bringing up politics because you want to get into pointless internet arguments'. Before adopting general-use rhetorical patterns, consider (reasonable) worst-case scenarios.

When you say something atypical, people will try very hard to fit you into a known pattern to compress your message. You can work to repeatedly correct their misconceptions until they finally create a never-before-used schema to fit you in, but in the meantime it's helpful if the interim frameworks they use to make sense of what you're saying are benign. Video games are about as benign as I could come up with, for youth/internet cultures.